diff --git a/dlls/msi/action.c b/dlls/msi/action.c
index f29be2b0390..0017de72a75 100644
--- a/dlls/msi/action.c
+++ b/dlls/msi/action.c
@@ -353,7 +353,7 @@ UINT msi_parse_command_line( MSIPACKAGE *package, LPCWSTR szCommandLine,
         remove_quotes( val );
         TRACE("Found commandline property %s = %s\n", debugstr_w(prop), debugstr_w(val));
 
-        r = msi_set_property( package->db, prop, val );
+        r = msi_set_property( package->db, prop, val, -1 );
         if (r == ERROR_SUCCESS && !strcmpW( prop, szSourceDir ))
             msi_reset_folders( package, TRUE );
 
@@ -462,7 +462,7 @@ UINT msi_set_sourcedir_props(MSIPACKAGE *package, BOOL replace)
     check = msi_dup_property( package->db, szSourceDir );
     if (!check || replace)
     {
-        UINT r = msi_set_property( package->db, szSourceDir, source );
+        UINT r = msi_set_property( package->db, szSourceDir, source, -1 );
         if (r == ERROR_SUCCESS)
             msi_reset_folders( package, TRUE );
     }
@@ -470,7 +470,7 @@ UINT msi_set_sourcedir_props(MSIPACKAGE *package, BOOL replace)
 
     check = msi_dup_property( package->db, szSOURCEDIR );
     if (!check || replace)
-        msi_set_property( package->db, szSOURCEDIR, source );
+        msi_set_property( package->db, szSOURCEDIR, source, -1 );
 
     msi_free( check );
     msi_free( source );
@@ -605,7 +605,7 @@ static UINT ACTION_ProcessExecSequence(MSIPACKAGE *package, BOOL UIran)
     {
         TRACE("Running the actions\n");
 
-        msi_set_property(package->db, szSourceDir, NULL);
+        msi_set_property( package->db, szSourceDir, NULL, -1 );
         rc = MSI_IterateRecords(view, NULL, ITERATE_Actions, package);
         msiobj_release(&view->hdr);
     }
@@ -1568,8 +1568,8 @@ static UINT load_all_folders( MSIPACKAGE *package )
 
 static UINT ACTION_CostInitialize(MSIPACKAGE *package)
 {
-    msi_set_property( package->db, szCostingComplete, szZero );
-    msi_set_property( package->db, szRootDrive, szCRoot );
+    msi_set_property( package->db, szCostingComplete, szZero, -1 );
+    msi_set_property( package->db, szRootDrive, szCRoot, -1 );
 
     load_all_folders( package );
     msi_load_all_components( package );
@@ -1785,7 +1785,7 @@ static BOOL process_overrides( MSIPACKAGE *package, int level )
     ret |= process_state_property( package, level, szAdvertise, INSTALLSTATE_ADVERTISED );
 
     if (ret)
-        msi_set_property( package->db, szPreselected, szOne );
+        msi_set_property( package->db, szPreselected, szOne, -1 );
 
     return ret;
 }
@@ -2361,7 +2361,7 @@ void msi_resolve_target_folder( MSIPACKAGE *package, const WCHAR *name, BOOL loa
         msi_free( normalized_path );
         return;
     }
-    msi_set_property( package->db, folder->Directory, normalized_path );
+    msi_set_property( package->db, folder->Directory, normalized_path, -1 );
     msi_free( folder->ResolvedTarget );
     folder->ResolvedTarget = normalized_path;
 
@@ -2422,15 +2422,15 @@ static UINT ACTION_CostFinalize(MSIPACKAGE *package)
     TRACE("Calculating file cost\n");
     calculate_file_cost( package );
 
-    msi_set_property( package->db, szCostingComplete, szOne );
+    msi_set_property( package->db, szCostingComplete, szOne, -1 );
     /* set default run level if not set */
     level = msi_dup_property( package->db, szInstallLevel );
     if (!level)
-        msi_set_property( package->db, szInstallLevel, szOne );
+        msi_set_property( package->db, szInstallLevel, szOne, -1 );
     msi_free(level);
 
     /* FIXME: check volume disk space */
-    msi_set_property( package->db, szOutOfDiskSpace, szZero );
+    msi_set_property( package->db, szOutOfDiskSpace, szZero, -1 );
 
     return MSI_SetFeatureStates(package);
 }
@@ -7006,7 +7006,7 @@ UINT msi_validate_product_id( MSIPACKAGE *package )
     if (key && template)
     {
         FIXME( "partial stub: template %s key %s\n", debugstr_w(template), debugstr_w(key) );
-        r = msi_set_property( package->db, szProductID, key );
+        r = msi_set_property( package->db, szProductID, key, -1 );
     }
     msi_free( template );
     msi_free( key );
@@ -7046,7 +7046,7 @@ static UINT ACTION_DisableRollback( MSIPACKAGE *package )
 {
     TRACE("%p\n", package);
 
-    msi_set_property( package->db, szRollbackDisabled, szOne );
+    msi_set_property( package->db, szRollbackDisabled, szOne, -1 );
     return ERROR_SUCCESS;
 }
 
@@ -7567,7 +7567,7 @@ UINT MSI_InstallPackage( MSIPACKAGE *package, LPCWSTR szPackagePath,
     BOOL ui_exists;
     UINT rc;
 
-    msi_set_property( package->db, szAction, szInstall );
+    msi_set_property( package->db, szAction, szInstall, -1 );
 
     package->script->InWhatSequence = SEQUENCE_INSTALL;
 
@@ -7617,7 +7617,7 @@ UINT MSI_InstallPackage( MSIPACKAGE *package, LPCWSTR szPackagePath,
     if (!szCommandLine && msi_get_property_int( package->db, szInstalled, 0 ))
     {
         TRACE("setting reinstall property\n");
-        msi_set_property( package->db, szReinstall, szAll );
+        msi_set_property( package->db, szReinstall, szAll, -1 );
     }
 
     /* properties may have been added by a transform */
@@ -7630,7 +7630,7 @@ UINT MSI_InstallPackage( MSIPACKAGE *package, LPCWSTR szPackagePath,
     if (msi_get_property_int( package->db, szDisableRollback, 0 ))
     {
         TRACE("disabling rollback\n");
-        msi_set_property( package->db, szRollbackDisabled, szOne );
+        msi_set_property( package->db, szRollbackDisabled, szOne, -1 );
     }
 
     if (needs_ui_sequence( package))
diff --git a/dlls/msi/appsearch.c b/dlls/msi/appsearch.c
index 21daf43f334..0d9c3022f09 100644
--- a/dlls/msi/appsearch.c
+++ b/dlls/msi/appsearch.c
@@ -1093,7 +1093,7 @@ static UINT iterate_appsearch(MSIRECORD *row, LPVOID param)
     r = ACTION_AppSearchSigName(package, sigName, &sig, &value);
     if (value)
     {
-        r = msi_set_property( package->db, propName, value );
+        r = msi_set_property( package->db, propName, value, -1 );
         if (r == ERROR_SUCCESS && !strcmpW( propName, szSourceDir ))
             msi_reset_folders( package, TRUE );
 
@@ -1153,7 +1153,7 @@ static UINT ITERATE_CCPSearch(MSIRECORD *row, LPVOID param)
     if (value)
     {
         TRACE("Found signature %s\n", debugstr_w(signature));
-        msi_set_property(package->db, success, szOne);
+        msi_set_property( package->db, success, szOne, -1 );
         msi_free(value);
         r = ERROR_NO_MORE_ITEMS;
     }
diff --git a/dlls/msi/custom.c b/dlls/msi/custom.c
index 8f32e590300..a3c253a0cf0 100644
--- a/dlls/msi/custom.c
+++ b/dlls/msi/custom.c
@@ -184,25 +184,21 @@ static LPWSTR msi_get_deferred_action(LPCWSTR action, LPCWSTR actiondata,
     return deferred;
 }
 
-static void set_deferred_action_props(MSIPACKAGE *package, LPWSTR deferred_data)
+static void set_deferred_action_props( MSIPACKAGE *package, const WCHAR *deferred_data )
 {
-    LPWSTR end, beg = deferred_data + 1;
-
     static const WCHAR sep[] = {'<','=','>',0};
+    const WCHAR *end, *beg = deferred_data + 1;
 
     end = strstrW(beg, sep);
-    *end = '\0';
-    msi_set_property(package->db, szCustomActionData, beg);
+    msi_set_property( package->db, szCustomActionData, beg, end - beg );
     beg = end + 3;
 
     end = strstrW(beg, sep);
-    *end = '\0';
-    msi_set_property(package->db, szUserSID, beg);
+    msi_set_property( package->db, szUserSID, beg, end - beg );
     beg = end + 3;
 
     end = strchrW(beg, ']');
-    *end = '\0';
-    msi_set_property(package->db, szProductCode, beg);
+    msi_set_property( package->db, szProductCode, beg, end - beg );
 }
 
 static MSIBINARY *create_temp_binary( MSIPACKAGE *package, LPCWSTR source, BOOL dll )
@@ -1284,9 +1280,9 @@ UINT ACTION_CustomAction(MSIPACKAGE *package, LPCWSTR action, UINT script, BOOL
             if (deferred_data)
                 set_deferred_action_props(package, deferred_data);
             else if (actiondata)
-                msi_set_property(package->db, szCustomActionData, actiondata);
+                msi_set_property( package->db, szCustomActionData, actiondata, -1 );
             else
-                msi_set_property(package->db, szCustomActionData, szEmpty);
+                msi_set_property( package->db, szCustomActionData, szEmpty, -1 );
 
             msi_free(actiondata);
         }
@@ -1335,7 +1331,7 @@ UINT ACTION_CustomAction(MSIPACKAGE *package, LPCWSTR action, UINT script, BOOL
                 break;
 
             deformat_string(package,target,&deformated);
-            rc = msi_set_property( package->db, source, deformated );
+            rc = msi_set_property( package->db, source, deformated, -1 );
             if (rc == ERROR_SUCCESS && !strcmpW( source, szSourceDir ))
                 msi_reset_folders( package, TRUE );
             msi_free(deformated);
diff --git a/dlls/msi/dialog.c b/dlls/msi/dialog.c
index 66d87864c52..85d58592e7f 100644
--- a/dlls/msi/dialog.c
+++ b/dlls/msi/dialog.c
@@ -583,7 +583,7 @@ static void msi_dialog_update_controls( msi_dialog *dialog, LPCWSTR property )
 
 static void msi_dialog_set_property( MSIPACKAGE *package, LPCWSTR property, LPCWSTR value )
 {
-    UINT r = msi_set_property( package->db, property, value );
+    UINT r = msi_set_property( package->db, property, value, -1 );
     if (r == ERROR_SUCCESS && !strcmpW( property, szSourceDir ))
         msi_reset_folders( package, TRUE );
 }
@@ -3939,7 +3939,7 @@ static UINT error_dialog_handler(MSIPACKAGE *package, LPCWSTR event,
     if ( !strcmpW( argument, error_abort ) || !strcmpW( argument, error_cancel ) ||
          !strcmpW( argument, error_no ) )
     {
-         msi_set_property( package->db, result_prop, error_abort );
+         msi_set_property( package->db, result_prop, error_abort, -1 );
     }
 
     ControlEvent_CleanupSubscriptions(package);
diff --git a/dlls/msi/events.c b/dlls/msi/events.c
index d42ac5b4e99..707a4a235fd 100644
--- a/dlls/msi/events.c
+++ b/dlls/msi/events.c
@@ -173,7 +173,7 @@ static UINT ControlEvent_AddLocal( MSIPACKAGE *package, LPCWSTR argument, msi_di
         if (!strcmpW( argument, feature->Feature ) || !strcmpW( argument, szAll ))
         {
             if (feature->ActionRequest != INSTALLSTATE_LOCAL)
-                msi_set_property( package->db, szPreselected, szOne );
+                msi_set_property( package->db, szPreselected, szOne, -1 );
             MSI_SetFeatureStateW( package, feature->Feature, INSTALLSTATE_LOCAL );
         }
     }
@@ -189,7 +189,7 @@ static UINT ControlEvent_Remove( MSIPACKAGE *package, LPCWSTR argument, msi_dial
         if (!strcmpW( argument, feature->Feature ) || !strcmpW( argument, szAll ))
         {
             if (feature->ActionRequest != INSTALLSTATE_ABSENT)
-                msi_set_property( package->db, szPreselected, szOne );
+                msi_set_property( package->db, szPreselected, szOne, -1 );
             MSI_SetFeatureStateW( package, feature->Feature, INSTALLSTATE_ABSENT );
         }
     }
@@ -205,7 +205,7 @@ static UINT ControlEvent_AddSource( MSIPACKAGE *package, LPCWSTR argument, msi_d
         if (!strcmpW( argument, feature->Feature ) || !strcmpW( argument, szAll ))
         {
             if (feature->ActionRequest != INSTALLSTATE_SOURCE)
-                msi_set_property( package->db, szPreselected, szOne );
+                msi_set_property( package->db, szPreselected, szOne, -1 );
             MSI_SetFeatureStateW( package, feature->Feature, INSTALLSTATE_SOURCE );
         }
     }
@@ -377,13 +377,13 @@ static UINT ControlEvent_DirectoryListUp(MSIPACKAGE *package, LPCWSTR argument,
 static UINT ControlEvent_ReinstallMode(MSIPACKAGE *package, LPCWSTR argument,
                                        msi_dialog *dialog)
 {
-    return msi_set_property( package->db, szReinstallMode, argument );
+    return msi_set_property( package->db, szReinstallMode, argument, -1 );
 }
 
 static UINT ControlEvent_Reinstall( MSIPACKAGE *package, LPCWSTR argument,
                                     msi_dialog *dialog )
 {
-    return msi_set_property( package->db, szReinstall, argument );
+    return msi_set_property( package->db, szReinstall, argument, -1 );
 }
 
 static UINT ControlEvent_ValidateProductID(MSIPACKAGE *package, LPCWSTR argument,
diff --git a/dlls/msi/install.c b/dlls/msi/install.c
index a6c832a94eb..e787714f433 100644
--- a/dlls/msi/install.c
+++ b/dlls/msi/install.c
@@ -558,7 +558,7 @@ static void set_target_path( MSIPACKAGE *package, MSIFOLDER *folder, const WCHAR
     {
         msi_free( folder->ResolvedTarget );
         folder->ResolvedTarget = target_path;
-        msi_set_property( package->db, folder->Directory, folder->ResolvedTarget );
+        msi_set_property( package->db, folder->Directory, folder->ResolvedTarget, -1 );
 
         LIST_FOR_EACH_ENTRY( fl, &folder->children, FolderList, entry )
         {
@@ -1650,6 +1650,7 @@ UINT MSI_SetInstallLevel( MSIPACKAGE *package, int iInstallLevel )
 {
     static const WCHAR fmt[] = { '%','d',0 };
     WCHAR level[6];
+    int len;
     UINT r;
 
     TRACE("%p %i\n", package, iInstallLevel);
@@ -1660,8 +1661,8 @@ UINT MSI_SetInstallLevel( MSIPACKAGE *package, int iInstallLevel )
     if (iInstallLevel < 1)
         return MSI_SetFeatureStates( package );
 
-    sprintfW( level, fmt, iInstallLevel );
-    r = msi_set_property( package->db, szInstallLevel, level );
+    len = sprintfW( level, fmt, iInstallLevel );
+    r = msi_set_property( package->db, szInstallLevel, level, len );
     if ( r == ERROR_SUCCESS )
         r = MSI_SetFeatureStates( package );
 
diff --git a/dlls/msi/msipriv.h b/dlls/msi/msipriv.h
index 897353e7c50..6d858f82af2 100644
--- a/dlls/msi/msipriv.h
+++ b/dlls/msi/msipriv.h
@@ -1003,7 +1003,7 @@ extern UINT ACTION_MsiUnpublishAssemblies(MSIPACKAGE *package) DECLSPEC_HIDDEN;
 extern DWORD deformat_string(MSIPACKAGE *package, LPCWSTR ptr, WCHAR** data ) DECLSPEC_HIDDEN;
 extern WCHAR *msi_dup_record_field(MSIRECORD *row, INT index) DECLSPEC_HIDDEN;
 extern LPWSTR msi_dup_property( MSIDATABASE *db, LPCWSTR prop ) DECLSPEC_HIDDEN;
-extern UINT msi_set_property( MSIDATABASE *, LPCWSTR, LPCWSTR ) DECLSPEC_HIDDEN;
+extern UINT msi_set_property( MSIDATABASE *, const WCHAR *, const WCHAR *, int ) DECLSPEC_HIDDEN;
 extern UINT msi_get_property( MSIDATABASE *, LPCWSTR, LPWSTR, LPDWORD ) DECLSPEC_HIDDEN;
 extern int msi_get_property_int( MSIDATABASE *package, LPCWSTR prop, int def ) DECLSPEC_HIDDEN;
 extern WCHAR *msi_resolve_source_folder(MSIPACKAGE *package, const WCHAR *name, MSIFOLDER **folder) DECLSPEC_HIDDEN;
diff --git a/dlls/msi/package.c b/dlls/msi/package.c
index 6528b85fd0c..3feddacc1ac 100644
--- a/dlls/msi/package.c
+++ b/dlls/msi/package.c
@@ -483,7 +483,7 @@ static UINT set_installed_prop( MSIPACKAGE *package )
     if (r == ERROR_SUCCESS)
     {
         RegCloseKey( hkey );
-        msi_set_property( package->db, szInstalled, szOne );
+        msi_set_property( package->db, szInstalled, szOne, -1 );
     }
     return r;
 }
@@ -525,7 +525,7 @@ static UINT set_user_sid_prop( MSIPACKAGE *package )
     if (!ConvertSidToStringSidW( psid, &sid_str ))
         goto done;
 
-    r = msi_set_property( package->db, szUserSID, sid_str );
+    r = msi_set_property( package->db, szUserSID, sid_str, -1 );
 
 done:
     LocalFree( sid_str );
@@ -657,7 +657,7 @@ static void set_msi_assembly_prop(MSIPACKAGE *package)
     if (!val_len || !verstr)
         goto done;
 
-    msi_set_property(package->db, netasm, verstr);
+    msi_set_property( package->db, netasm, verstr, -1 );
 
 done:
     msi_free(fusion);
@@ -757,182 +757,182 @@ static VOID set_installer_properties(MSIPACKAGE *package)
 
     SHGetFolderPathW(NULL, CSIDL_COMMON_APPDATA, NULL, 0, pth);
     strcatW(pth, szBackSlash);
-    msi_set_property(package->db, szCommonAppDataFolder, pth);
+    msi_set_property( package->db, szCommonAppDataFolder, pth, -1 );
 
     SHGetFolderPathW(NULL, CSIDL_FAVORITES, NULL, 0, pth);
     strcatW(pth, szBackSlash);
-    msi_set_property(package->db, szFavoritesFolder, pth);
+    msi_set_property( package->db, szFavoritesFolder, pth, -1 );
 
     SHGetFolderPathW(NULL, CSIDL_FONTS, NULL, 0, pth);
     strcatW(pth, szBackSlash);
-    msi_set_property(package->db, szFontsFolder, pth);
+    msi_set_property( package->db, szFontsFolder, pth, -1 );
 
     SHGetFolderPathW(NULL, CSIDL_SENDTO, NULL, 0, pth);
     strcatW(pth, szBackSlash);
-    msi_set_property(package->db, szSendToFolder, pth);
+    msi_set_property( package->db, szSendToFolder, pth, -1 );
 
     SHGetFolderPathW(NULL, CSIDL_STARTMENU, NULL, 0, pth);
     strcatW(pth, szBackSlash);
-    msi_set_property(package->db, szStartMenuFolder, pth);
+    msi_set_property( package->db, szStartMenuFolder, pth, -1 );
 
     SHGetFolderPathW(NULL, CSIDL_STARTUP, NULL, 0, pth);
     strcatW(pth, szBackSlash);
-    msi_set_property(package->db, szStartupFolder, pth);
+    msi_set_property( package->db, szStartupFolder, pth, -1 );
 
     SHGetFolderPathW(NULL, CSIDL_TEMPLATES, NULL, 0, pth);
     strcatW(pth, szBackSlash);
-    msi_set_property(package->db, szTemplateFolder, pth);
+    msi_set_property( package->db, szTemplateFolder, pth, -1 );
 
     SHGetFolderPathW(NULL, CSIDL_DESKTOP, NULL, 0, pth);
     strcatW(pth, szBackSlash);
-    msi_set_property(package->db, szDesktopFolder, pth);
+    msi_set_property( package->db, szDesktopFolder, pth, -1 );
 
     /* FIXME: set to AllUsers profile path if ALLUSERS is set */
     SHGetFolderPathW(NULL, CSIDL_PROGRAMS, NULL, 0, pth);
     strcatW(pth, szBackSlash);
-    msi_set_property(package->db, szProgramMenuFolder, pth);
+    msi_set_property( package->db, szProgramMenuFolder, pth, -1 );
 
     SHGetFolderPathW(NULL, CSIDL_ADMINTOOLS, NULL, 0, pth);
     strcatW(pth, szBackSlash);
-    msi_set_property(package->db, szAdminToolsFolder, pth);
+    msi_set_property( package->db, szAdminToolsFolder, pth, -1 );
 
     SHGetFolderPathW(NULL, CSIDL_APPDATA, NULL, 0, pth);
     strcatW(pth, szBackSlash);
-    msi_set_property(package->db, szAppDataFolder, pth);
+    msi_set_property( package->db, szAppDataFolder, pth, -1 );
 
     SHGetFolderPathW(NULL, CSIDL_SYSTEM, NULL, 0, pth);
     strcatW(pth, szBackSlash);
-    msi_set_property(package->db, szSystemFolder, pth);
-    msi_set_property(package->db, szSystem16Folder, pth);
+    msi_set_property( package->db, szSystemFolder, pth, -1 );
+    msi_set_property( package->db, szSystem16Folder, pth, -1 );
 
     SHGetFolderPathW(NULL, CSIDL_LOCAL_APPDATA, NULL, 0, pth);
     strcatW(pth, szBackSlash);
-    msi_set_property(package->db, szLocalAppDataFolder, pth);
+    msi_set_property( package->db, szLocalAppDataFolder, pth, -1 );
 
     SHGetFolderPathW(NULL, CSIDL_MYPICTURES, NULL, 0, pth);
     strcatW(pth, szBackSlash);
-    msi_set_property(package->db, szMyPicturesFolder, pth);
+    msi_set_property( package->db, szMyPicturesFolder, pth, -1 );
 
     SHGetFolderPathW(NULL, CSIDL_PERSONAL, NULL, 0, pth);
     strcatW(pth, szBackSlash);
-    msi_set_property(package->db, szPersonalFolder, pth);
+    msi_set_property( package->db, szPersonalFolder, pth, -1 );
 
     SHGetFolderPathW(NULL, CSIDL_WINDOWS, NULL, 0, pth);
     strcatW(pth, szBackSlash);
-    msi_set_property(package->db, szWindowsFolder, pth);
+    msi_set_property( package->db, szWindowsFolder, pth, -1 );
     
     SHGetFolderPathW(NULL, CSIDL_PRINTHOOD, NULL, 0, pth);
     strcatW(pth, szBackSlash);
-    msi_set_property(package->db, szPrintHoodFolder, pth);
+    msi_set_property( package->db, szPrintHoodFolder, pth, -1 );
 
     SHGetFolderPathW(NULL, CSIDL_NETHOOD, NULL, 0, pth);
     strcatW(pth, szBackSlash);
-    msi_set_property(package->db, szNetHoodFolder, pth);
+    msi_set_property( package->db, szNetHoodFolder, pth, -1 );
 
     SHGetFolderPathW(NULL, CSIDL_RECENT, NULL, 0, pth);
     strcatW(pth, szBackSlash);
-    msi_set_property(package->db, szRecentFolder, pth);
+    msi_set_property( package->db, szRecentFolder, pth, -1 );
 
     /* Physical Memory is specified in MB. Using total amount. */
     msex.dwLength = sizeof(msex);
     GlobalMemoryStatusEx( &msex );
-    sprintfW( bufstr, szIntFormat, (int)(msex.ullTotalPhys / 1024 / 1024) );
-    msi_set_property(package->db, szPhysicalMemory, bufstr);
+    len = sprintfW( bufstr, szIntFormat, (int)(msex.ullTotalPhys / 1024 / 1024) );
+    msi_set_property( package->db, szPhysicalMemory, bufstr, len );
 
     SHGetFolderPathW(NULL, CSIDL_WINDOWS, NULL, 0, pth);
     ptr = strchrW(pth,'\\');
     if (ptr) *(ptr + 1) = 0;
-    msi_set_property(package->db, szWindowsVolume, pth);
+    msi_set_property( package->db, szWindowsVolume, pth, -1 );
     
-    GetTempPathW(MAX_PATH,pth);
-    msi_set_property(package->db, szTempFolder, pth);
+    len = GetTempPathW(MAX_PATH, pth);
+    msi_set_property( package->db, szTempFolder, pth, len );
 
     /* in a wine environment the user is always admin and privileged */
-    msi_set_property(package->db, szAdminUser, szOne);
-    msi_set_property(package->db, szPrivileged, szOne);
+    msi_set_property( package->db, szAdminUser, szOne, -1 );
+    msi_set_property( package->db, szPrivileged, szOne, -1 );
 
     /* set the os things */
     OSVersion.dwOSVersionInfoSize = sizeof(OSVERSIONINFOEXW);
     GetVersionExW((OSVERSIONINFOW *)&OSVersion);
     verval = OSVersion.dwMinorVersion + OSVersion.dwMajorVersion * 100;
-    sprintfW(verstr, szFormat, verval);
+    len = sprintfW( verstr, szFormat, verval );
     switch (OSVersion.dwPlatformId)
     {
         case VER_PLATFORM_WIN32_WINDOWS:    
-            msi_set_property(package->db, szVersion9x, verstr);
+            msi_set_property( package->db, szVersion9x, verstr, len );
             break;
         case VER_PLATFORM_WIN32_NT:
-            msi_set_property(package->db, szVersionNT, verstr);
-            sprintfW(verstr, szFormat,OSVersion.wProductType);
-            msi_set_property(package->db, szMsiNTProductType, verstr);
+            msi_set_property( package->db, szVersionNT, verstr, len );
+            len = sprintfW( verstr, szFormat,OSVersion.wProductType );
+            msi_set_property( package->db, szMsiNTProductType, verstr, len );
             break;
     }
-    sprintfW(verstr, szFormat, OSVersion.dwBuildNumber);
-    msi_set_property(package->db, szWindowsBuild, verstr);
-    sprintfW(verstr, szFormat, OSVersion.wServicePackMajor);
-    msi_set_property(package->db, szServicePackLevel, verstr);
+    len = sprintfW( verstr, szFormat, OSVersion.dwBuildNumber );
+    msi_set_property( package->db, szWindowsBuild, verstr, len );
+    len = sprintfW( verstr, szFormat, OSVersion.wServicePackMajor );
+    msi_set_property( package->db, szServicePackLevel, verstr, len );
 
-    sprintfW( bufstr, szFormat2, MSI_MAJORVERSION, MSI_MINORVERSION);
-    msi_set_property( package->db, szVersionMsi, bufstr );
-    sprintfW( bufstr, szFormat, MSI_MAJORVERSION * 100);
-    msi_set_property( package->db, szVersionDatabase, bufstr );
+    len = sprintfW( bufstr, szFormat2, MSI_MAJORVERSION, MSI_MINORVERSION );
+    msi_set_property( package->db, szVersionMsi, bufstr, len );
+    len = sprintfW( bufstr, szFormat, MSI_MAJORVERSION * 100 );
+    msi_set_property( package->db, szVersionDatabase, bufstr, len );
 
     GetNativeSystemInfo( &sys_info );
-    sprintfW( bufstr, szIntFormat, sys_info.wProcessorLevel );
-    msi_set_property( package->db, szIntel, bufstr );
+    len = sprintfW( bufstr, szIntFormat, sys_info.wProcessorLevel );
+    msi_set_property( package->db, szIntel, bufstr, len );
     if (sys_info.u.s.wProcessorArchitecture == PROCESSOR_ARCHITECTURE_INTEL)
     {
         GetSystemDirectoryW( pth, MAX_PATH );
         PathAddBackslashW( pth );
-        msi_set_property( package->db, szSystemFolder, pth );
+        msi_set_property( package->db, szSystemFolder, pth, -1 );
 
         SHGetFolderPathW( NULL, CSIDL_PROGRAM_FILES, NULL, 0, pth );
         PathAddBackslashW( pth );
-        msi_set_property( package->db, szProgramFilesFolder, pth );
+        msi_set_property( package->db, szProgramFilesFolder, pth, -1 );
 
         SHGetFolderPathW( NULL, CSIDL_PROGRAM_FILES_COMMON, NULL, 0, pth );
         PathAddBackslashW( pth );
-        msi_set_property( package->db, szCommonFilesFolder, pth );
+        msi_set_property( package->db, szCommonFilesFolder, pth, -1 );
     }
     else if (sys_info.u.s.wProcessorArchitecture == PROCESSOR_ARCHITECTURE_AMD64)
     {
-        msi_set_property( package->db, szMsiAMD64, bufstr );
-        msi_set_property( package->db, szMsix64, bufstr );
-        msi_set_property( package->db, szVersionNT64, verstr );
+        msi_set_property( package->db, szMsiAMD64, bufstr, -1 );
+        msi_set_property( package->db, szMsix64, bufstr, -1 );
+        msi_set_property( package->db, szVersionNT64, verstr, -1 );
 
         GetSystemDirectoryW( pth, MAX_PATH );
         PathAddBackslashW( pth );
-        msi_set_property( package->db, szSystem64Folder, pth );
+        msi_set_property( package->db, szSystem64Folder, pth, -1 );
 
         GetSystemWow64DirectoryW( pth, MAX_PATH );
         PathAddBackslashW( pth );
-        msi_set_property( package->db, szSystemFolder, pth );
+        msi_set_property( package->db, szSystemFolder, pth, -1 );
 
         SHGetFolderPathW( NULL, CSIDL_PROGRAM_FILES, NULL, 0, pth );
         PathAddBackslashW( pth );
-        msi_set_property( package->db, szProgramFiles64Folder, pth );
+        msi_set_property( package->db, szProgramFiles64Folder, pth, -1 );
 
         SHGetFolderPathW( NULL, CSIDL_PROGRAM_FILESX86, NULL, 0, pth );
         PathAddBackslashW( pth );
-        msi_set_property( package->db, szProgramFilesFolder, pth );
+        msi_set_property( package->db, szProgramFilesFolder, pth, -1 );
 
         SHGetFolderPathW( NULL, CSIDL_PROGRAM_FILES_COMMON, NULL, 0, pth );
         PathAddBackslashW( pth );
-        msi_set_property( package->db, szCommonFiles64Folder, pth );
+        msi_set_property( package->db, szCommonFiles64Folder, pth, -1 );
 
         SHGetFolderPathW( NULL, CSIDL_PROGRAM_FILES_COMMONX86, NULL, 0, pth );
         PathAddBackslashW( pth );
-        msi_set_property( package->db, szCommonFilesFolder, pth );
+        msi_set_property( package->db, szCommonFilesFolder, pth, -1 );
     }
 
     /* Screen properties. */
     dc = GetDC(0);
-    sprintfW( bufstr, szIntFormat, GetDeviceCaps( dc, HORZRES ) );
-    msi_set_property( package->db, szScreenX, bufstr );
-    sprintfW( bufstr, szIntFormat, GetDeviceCaps( dc, VERTRES ));
-    msi_set_property( package->db, szScreenY, bufstr );
-    sprintfW( bufstr, szIntFormat, GetDeviceCaps( dc, BITSPIXEL ));
-    msi_set_property( package->db, szColorBits, bufstr );
+    len = sprintfW( bufstr, szIntFormat, GetDeviceCaps(dc, HORZRES) );
+    msi_set_property( package->db, szScreenX, bufstr, len );
+    len = sprintfW( bufstr, szIntFormat, GetDeviceCaps(dc, VERTRES) );
+    msi_set_property( package->db, szScreenY, bufstr, len );
+    len = sprintfW( bufstr, szIntFormat, GetDeviceCaps(dc, BITSPIXEL) );
+    msi_set_property( package->db, szColorBits, bufstr, len );
     ReleaseDC(0, dc);
 
     /* USERNAME and COMPANYNAME */
@@ -944,10 +944,10 @@ static VOID set_installer_properties(MSIPACKAGE *package)
     {
         if (!username &&
             (username = msi_reg_get_val_str( hkey, szDefName )))
-            msi_set_property( package->db, szUSERNAME, username );
+            msi_set_property( package->db, szUSERNAME, username, -1 );
         if (!companyname &&
             (companyname = msi_reg_get_val_str( hkey, szDefCompany )))
-            msi_set_property( package->db, szCOMPANYNAME, companyname );
+            msi_set_property( package->db, szCOMPANYNAME, companyname, -1 );
         CloseHandle( hkey );
     }
     if ((!username || !companyname) &&
@@ -955,10 +955,10 @@ static VOID set_installer_properties(MSIPACKAGE *package)
     {
         if (!username &&
             (username = msi_reg_get_val_str( hkey, szRegisteredUser )))
-            msi_set_property( package->db, szUSERNAME, username );
+            msi_set_property( package->db, szUSERNAME, username, -1 );
         if (!companyname &&
             (companyname = msi_reg_get_val_str( hkey, szRegisteredOrganization )))
-            msi_set_property( package->db, szCOMPANYNAME, companyname );
+            msi_set_property( package->db, szCOMPANYNAME, companyname, -1 );
         CloseHandle( hkey );
     }
     msi_free( username );
@@ -971,7 +971,7 @@ static VOID set_installer_properties(MSIPACKAGE *package)
     GetSystemTime( &systemtime );
     if (GetDateFormatW( LOCALE_USER_DEFAULT, DATE_SHORTDATE, &systemtime,
                         NULL, bufstr, sizeof(bufstr)/sizeof(bufstr[0]) ))
-        msi_set_property( package->db, szDate, bufstr );
+        msi_set_property( package->db, szDate, bufstr, -1 );
     else
         ERR("Couldn't set Date property: GetDateFormat failed with error %d\n", GetLastError());
 
@@ -979,22 +979,22 @@ static VOID set_installer_properties(MSIPACKAGE *package)
                         TIME_FORCE24HOURFORMAT | TIME_NOTIMEMARKER,
                         &systemtime, NULL, bufstr,
                         sizeof(bufstr)/sizeof(bufstr[0]) ))
-        msi_set_property( package->db, szTime, bufstr );
+        msi_set_property( package->db, szTime, bufstr, -1 );
     else
         ERR("Couldn't set Time property: GetTimeFormat failed with error %d\n", GetLastError());
 
     set_msi_assembly_prop( package );
 
     langid = GetUserDefaultLangID();
-    sprintfW(bufstr, szIntFormat, langid);
-    msi_set_property( package->db, szUserLanguageID, bufstr );
+    len = sprintfW( bufstr, szIntFormat, langid );
+    msi_set_property( package->db, szUserLanguageID, bufstr, len );
 
     langid = GetSystemDefaultLangID();
-    sprintfW(bufstr, szIntFormat, langid);
-    msi_set_property( package->db, szSystemLangID, bufstr );
+    len = sprintfW( bufstr, szIntFormat, langid );
+    msi_set_property( package->db, szSystemLangID, bufstr, len );
 
-    sprintfW(bufstr, szIntFormat, MsiQueryProductStateW(package->ProductCode));
-    msi_set_property( package->db, szProductState, bufstr );
+    len = sprintfW( bufstr, szIntFormat, MsiQueryProductStateW(package->ProductCode) );
+    msi_set_property( package->db, szProductState, bufstr, len );
 
     len = 0;
     if (!GetUserNameW( NULL, &len ) && GetLastError() == ERROR_INSUFFICIENT_BUFFER)
@@ -1003,7 +1003,7 @@ static VOID set_installer_properties(MSIPACKAGE *package)
         if ((username = msi_alloc( len * sizeof(WCHAR) )))
         {
             if (GetUserNameW( username, &len ))
-                msi_set_property( package->db, szLogonUser, username );
+                msi_set_property( package->db, szLogonUser, username, len - 1 );
             msi_free( username );
         }
     }
@@ -1014,7 +1014,7 @@ static VOID set_installer_properties(MSIPACKAGE *package)
         if ((computername = msi_alloc( len * sizeof(WCHAR) )))
         {
             if (GetComputerNameW( computername, &len ))
-                msi_set_property( package->db, szComputerName, computername );
+                msi_set_property( package->db, szComputerName, computername, len - 1 );
             msi_free( computername );
         }
     }
@@ -1073,7 +1073,7 @@ static UINT msi_load_summary_properties( MSIPACKAGE *package )
         goto done;
     }
 
-    msi_set_property( package->db, szPackageCode, package_code );
+    msi_set_property( package->db, szPackageCode, package_code, len );
     msi_free( package_code );
 
     /* load package attributes */
@@ -1141,9 +1141,9 @@ void msi_adjust_privilege_properties( MSIPACKAGE *package )
     if (msi_get_property_int( package->db, szAllUsers, 0 ) == 2)
     {
         TRACE("resetting ALLUSERS property from 2 to 1\n");
-        msi_set_property( package->db, szAllUsers, szOne );
+        msi_set_property( package->db, szAllUsers, szOne, -1 );
     }
-    msi_set_property( package->db, szAdminUser, szOne );
+    msi_set_property( package->db, szAdminUser, szOne, -1 );
 }
 
 MSIPACKAGE *MSI_CreatePackage( MSIDATABASE *db, LPCWSTR base_url )
@@ -1151,6 +1151,7 @@ MSIPACKAGE *MSI_CreatePackage( MSIDATABASE *db, LPCWSTR base_url )
     static const WCHAR fmtW[] = {'%','u',0};
     MSIPACKAGE *package;
     WCHAR uilevel[11];
+    int len;
     UINT r;
 
     TRACE("%p\n", db);
@@ -1176,8 +1177,8 @@ MSIPACKAGE *MSI_CreatePackage( MSIDATABASE *db, LPCWSTR base_url )
         set_installer_properties( package );
 
         package->ui_level = gUILevel;
-        sprintfW( uilevel, fmtW, gUILevel & INSTALLUILEVEL_MASK );
-        msi_set_property(package->db, szUILevel, uilevel);
+        len = sprintfW( uilevel, fmtW, gUILevel & INSTALLUILEVEL_MASK );
+        msi_set_property( package->db, szUILevel, uilevel, len );
 
         r = msi_load_summary_properties( package );
         if (r != ERROR_SUCCESS)
@@ -1608,18 +1609,17 @@ UINT MSI_OpenPackageW(LPCWSTR szPackage, MSIPACKAGE **pPackage)
         msiobj_release( &package->hdr );
         return r;
     }
-    msi_set_property( package->db, szDatabase, db->path );
+    msi_set_property( package->db, szDatabase, db->path, -1 );
 
     if( UrlIsW( szPackage, URLIS_URL ) )
-        msi_set_property( package->db, szOriginalDatabase, szPackage );
+        msi_set_property( package->db, szOriginalDatabase, szPackage, -1 );
     else if( szPackage[0] == '#' )
-        msi_set_property( package->db, szOriginalDatabase, db->path );
+        msi_set_property( package->db, szOriginalDatabase, db->path, -1 );
     else
     {
         WCHAR fullpath[MAX_PATH];
-
-        GetFullPathNameW( szPackage, MAX_PATH, fullpath, NULL );
-        msi_set_property( package->db, szOriginalDatabase, fullpath );
+        DWORD len = GetFullPathNameW( szPackage, MAX_PATH, fullpath, NULL );
+        msi_set_property( package->db, szOriginalDatabase, fullpath, len );
     }
     msi_set_context( package );
 
@@ -2018,7 +2018,7 @@ void msi_reset_folders( MSIPACKAGE *package, BOOL source )
     }
 }
 
-UINT msi_set_property( MSIDATABASE *db, LPCWSTR szName, LPCWSTR szValue )
+UINT msi_set_property( MSIDATABASE *db, const WCHAR *name, const WCHAR *value, int len )
 {
     static const WCHAR insert_query[] = {
         'I','N','S','E','R','T',' ','I','N','T','O',' ',
@@ -2039,34 +2039,34 @@ UINT msi_set_property( MSIDATABASE *db, LPCWSTR szName, LPCWSTR szValue )
     WCHAR query[1024];
     UINT rc;
 
-    TRACE("%p %s %s\n", db, debugstr_w(szName), debugstr_w(szValue));
+    TRACE("%p %s %s %d\n", db, debugstr_w(name), debugstr_wn(value, len), len);
 
-    if (!szName)
+    if (!name)
         return ERROR_INVALID_PARAMETER;
 
     /* this one is weird... */
-    if (!szName[0])
-        return szValue ? ERROR_FUNCTION_FAILED : ERROR_SUCCESS;
+    if (!name[0])
+        return value ? ERROR_FUNCTION_FAILED : ERROR_SUCCESS;
 
-    rc = msi_get_property(db, szName, 0, &sz);
-    if (!szValue || !*szValue)
+    if (value && len < 0) len = strlenW( value );
+
+    rc = msi_get_property( db, name, 0, &sz );
+    if (!value || (!*value && !len))
     {
-        sprintfW(query, delete_query, szName);
+        sprintfW( query, delete_query, name );
     }
     else if (rc == ERROR_MORE_DATA || rc == ERROR_SUCCESS)
     {
-        sprintfW(query, update_query, szName);
-
+        sprintfW( query, update_query, name );
         row = MSI_CreateRecord(1);
-        MSI_RecordSetStringW(row, 1, szValue);
+        msi_record_set_string( row, 1, value, len );
     }
     else
     {
-        strcpyW(query, insert_query);
-
+        strcpyW( query, insert_query );
         row = MSI_CreateRecord(2);
-        MSI_RecordSetStringW(row, 1, szName);
-        MSI_RecordSetStringW(row, 2, szValue);
+        msi_record_set_string( row, 1, name, -1 );
+        msi_record_set_string( row, 2, value, len );
     }
 
     rc = MSI_DatabaseOpenViewW(db, query, &view);
@@ -2123,7 +2123,7 @@ UINT WINAPI MsiSetPropertyW( MSIHANDLE hInstall, LPCWSTR szName, LPCWSTR szValue
         return ERROR_SUCCESS;
     }
 
-    ret = msi_set_property( package->db, szName, szValue );
+    ret = msi_set_property( package->db, szName, szValue, -1 );
     if (ret == ERROR_SUCCESS && !strcmpW( szName, szSourceDir ))
         msi_reset_folders( package, TRUE );
 
diff --git a/dlls/msi/patch.c b/dlls/msi/patch.c
index 4801872b32b..59785a690f2 100644
--- a/dlls/msi/patch.c
+++ b/dlls/msi/patch.c
@@ -225,7 +225,7 @@ static UINT patch_set_media_source_prop( MSIPACKAGE *package )
     {
         property = MSI_RecordGetString( rec, 1 );
         patch = msi_dup_property( package->db, szPatch );
-        msi_set_property( package->db, property, patch );
+        msi_set_property( package->db, property, patch, -1 );
         msi_free( patch );
         msiobj_release( &rec->hdr );
     }
diff --git a/dlls/msi/upgrade.c b/dlls/msi/upgrade.c
index 94806610045..cd0ec06e6e2 100644
--- a/dlls/msi/upgrade.c
+++ b/dlls/msi/upgrade.c
@@ -88,7 +88,7 @@ static void append_productcode(MSIPACKAGE* package, LPCWSTR action_property,
         newprop[0] = 0;
     strcatW(newprop,productid);
 
-    r = msi_set_property( package->db, action_property, newprop );
+    r = msi_set_property( package->db, action_property, newprop, -1 );
     if (r == ERROR_SUCCESS && !strcmpW( action_property, szSourceDir ))
         msi_reset_folders( package, TRUE );