diff --git a/dlls/ntdll/actctx.c b/dlls/ntdll/actctx.c
index a1b1e3bd89c..80f69a83d1f 100644
--- a/dlls/ntdll/actctx.c
+++ b/dlls/ntdll/actctx.c
@@ -32,6 +32,7 @@
 #include "ntstatus.h"
 #define WIN32_NO_STATUS
 #include "winternl.h"
+#include "ddk/wdm.h"
 #include "ntdll_misc.h"
 #include "wine/exception.h"
 #include "wine/debug.h"
@@ -1877,11 +1878,12 @@ static NTSTATUS lookup_winsxs(struct actctx_loader* acl, struct assembly_identit
 
     if (!ai->arch || !ai->name || !ai->public_key) return STATUS_NO_SUCH_FILE;
 
-    if (!(path = RtlAllocateHeap( GetProcessHeap(), 0, windows_dir.Length + sizeof(manifest_dirW) )))
+    if (!(path = RtlAllocateHeap( GetProcessHeap(), 0, sizeof(manifest_dirW) +
+                                  strlenW(user_shared_data->NtSystemRoot) * sizeof(WCHAR) )))
         return STATUS_NO_MEMORY;
 
-    memcpy( path, windows_dir.Buffer, windows_dir.Length );
-    memcpy( path + windows_dir.Length/sizeof(WCHAR), manifest_dirW, sizeof(manifest_dirW) );
+    strcpyW( path, user_shared_data->NtSystemRoot );
+    memcpy( path + strlenW(path), manifest_dirW, sizeof(manifest_dirW) );
 
     if (!RtlDosPathNameToNtPathName_U( path, &path_us, NULL, NULL ))
     {
diff --git a/dlls/ntdll/directory.c b/dlls/ntdll/directory.c
index b57741a9eed..42b36393710 100644
--- a/dlls/ntdll/directory.c
+++ b/dlls/ntdll/directory.c
@@ -77,6 +77,7 @@
 #include "windef.h"
 #include "winnt.h"
 #include "winternl.h"
+#include "ddk/wdm.h"
 #include "ntdll_misc.h"
 #include "wine/unicode.h"
 #include "wine/server.h"
@@ -161,7 +162,6 @@ static int show_dot_files = -1;
 /* at some point we may want to allow Winelib apps to set this */
 static const int is_case_sensitive = FALSE;
 
-UNICODE_STRING windows_dir = { 0, 0, NULL };  /* windows directory */
 UNICODE_STRING system_dir = { 0, 0, NULL };  /* system directory */
 
 static struct file_identity curdir;
@@ -2282,16 +2282,16 @@ static void init_redirects(void)
     struct stat st;
     unsigned int i;
 
-    if (!RtlDosPathNameToNtPathName_U( windows_dir.Buffer, &nt_name, NULL, NULL ))
+    if (!RtlDosPathNameToNtPathName_U( user_shared_data->NtSystemRoot, &nt_name, NULL, NULL ))
     {
-        ERR( "can't convert %s\n", debugstr_us(&windows_dir) );
+        ERR( "can't convert %s\n", debugstr_w(user_shared_data->NtSystemRoot) );
         return;
     }
     status = wine_nt_to_unix_file_name( &nt_name, &unix_name, FILE_OPEN_IF, FALSE );
     RtlFreeUnicodeString( &nt_name );
     if (status)
     {
-        ERR( "cannot open %s (%x)\n", debugstr_us(&windows_dir), status );
+        ERR( "cannot open %s (%x)\n", debugstr_w(user_shared_data->NtSystemRoot), status );
         return;
     }
     if (!stat( unix_name.Buffer, &st ))
@@ -2389,7 +2389,6 @@ void DIR_init_windows_dir( const WCHAR *win, const WCHAR *sys )
 {
     /* FIXME: should probably store paths as NT file names */
 
-    RtlCreateUnicodeString( &windows_dir, win );
     RtlCreateUnicodeString( &system_dir, sys );
 
 #ifndef _WIN64
diff --git a/dlls/ntdll/loader.c b/dlls/ntdll/loader.c
index 4c8d7270b0f..5ee7d0ab166 100644
--- a/dlls/ntdll/loader.c
+++ b/dlls/ntdll/loader.c
@@ -1753,16 +1753,16 @@ static NTSTATUS find_actctx_dll( LPCWSTR libname, LPWSTR *fullname )
         }
     }
 
-    needed = (windows_dir.Length + sizeof(winsxsW) + info->ulAssemblyDirectoryNameLength +
-              nameW.Length + 2*sizeof(WCHAR));
+    needed = (strlenW(user_shared_data->NtSystemRoot) * sizeof(WCHAR) +
+              sizeof(winsxsW) + info->ulAssemblyDirectoryNameLength + nameW.Length + 2*sizeof(WCHAR));
 
     if (!(*fullname = p = RtlAllocateHeap( GetProcessHeap(), 0, needed )))
     {
         status = STATUS_NO_MEMORY;
         goto done;
     }
-    memcpy( p, windows_dir.Buffer, windows_dir.Length );
-    p += windows_dir.Length / sizeof(WCHAR);
+    strcpyW( p, user_shared_data->NtSystemRoot );
+    p += strlenW(p);
     memcpy( p, winsxsW, sizeof(winsxsW) );
     p += sizeof(winsxsW) / sizeof(WCHAR);
     memcpy( p, info->lpAssemblyDirectoryName, info->ulAssemblyDirectoryNameLength );
@@ -2812,8 +2812,8 @@ void CDECL __wine_init_windows_dir( const WCHAR *windir, const WCHAR *sysdir )
     PLIST_ENTRY mark, entry;
     LPWSTR buffer, p;
 
-    DIR_init_windows_dir( windir, sysdir );
     strcpyW( user_shared_data->NtSystemRoot, windir );
+    DIR_init_windows_dir( windir, sysdir );
 
     /* prepend the system dir to the name of the already created modules */
     mark = &NtCurrentTeb()->Peb->LdrData->InLoadOrderModuleList;
diff --git a/dlls/ntdll/ntdll_misc.h b/dlls/ntdll/ntdll_misc.h
index 77f8603a604..49565379200 100644
--- a/dlls/ntdll/ntdll_misc.h
+++ b/dlls/ntdll/ntdll_misc.h
@@ -107,7 +107,6 @@ extern FARPROC SNOOP_GetProcAddress( HMODULE hmod, const IMAGE_EXPORT_DIRECTORY
                                      FARPROC origfun, DWORD ordinal, const WCHAR *user ) DECLSPEC_HIDDEN;
 extern void RELAY_SetupDLL( HMODULE hmod ) DECLSPEC_HIDDEN;
 extern void SNOOP_SetupDLL( HMODULE hmod ) DECLSPEC_HIDDEN;
-extern UNICODE_STRING windows_dir DECLSPEC_HIDDEN;
 extern UNICODE_STRING system_dir DECLSPEC_HIDDEN;
 
 typedef LONG (WINAPI *PUNHANDLED_EXCEPTION_FILTER)(PEXCEPTION_POINTERS);