diff --git a/ole/stg_bigblockfile.c b/ole/stg_bigblockfile.c
index 13d52e7d9e2..ffd6776501f 100644
--- a/ole/stg_bigblockfile.c
+++ b/ole/stg_bigblockfile.c
@@ -86,6 +86,8 @@ static BigBlock* BIGBLOCKFILE_AddBigBlock(LPBIGBLOCKFILE This,
 					  ULONG          index);
 static BigBlock* BIGBLOCKFILE_CreateBlock(ULONG index);
 
+static DWORD BIGBLOCKFILE_GetProtectMode(DWORD openFlags);
+
 /******************************************************************************
  *      BIGBLOCKFILE_Construct
  *
@@ -95,6 +97,7 @@ static BigBlock* BIGBLOCKFILE_CreateBlock(ULONG index);
  */
 BigBlockFile * BIGBLOCKFILE_Construct(
   HANDLE32 hFile, 
+    DWORD    openFlags,
   ULONG    blocksize)
 {
   LPBIGBLOCKFILE This;
@@ -112,11 +115,13 @@ BigBlockFile * BIGBLOCKFILE_Construct(
     return NULL;
   }
 
+  This->flProtect = BIGBLOCKFILE_GetProtectMode(openFlags);
+
   /* create the file mapping object
    */
   This->hfilemap = CreateFileMapping32A(This->hfile,
 					NULL,
-					PAGE_READWRITE, 
+					This->flProtect, 
 					0, 0,
 					NULL);
   
@@ -327,7 +332,7 @@ void BIGBLOCKFILE_SetSize(LPBIGBLOCKFILE This, ULARGE_INTEGER newSize)
    */
   This->hfilemap = CreateFileMapping32A(This->hfile,
 					NULL,
-					PAGE_READWRITE, 
+					This->flProtect,
 					0, 0, 
 					NULL);
 
@@ -826,3 +831,26 @@ static void BIGBLOCKFILE_FreeAllMappedPages(
   }
 }
 
+/****************************************************************************
+ *      BIGBLOCKFILE_GetProtectMode
+ *
+ * This function will return a protection mode flag for a file-mapping object
+ * from the open flags of a file.
+ */
+static DWORD BIGBLOCKFILE_GetProtectMode(DWORD openFlags)
+{
+  DWORD flProtect        = PAGE_READONLY;
+  BOOL32 bSTGM_WRITE     = ((openFlags & STGM_WRITE) == STGM_WRITE);
+  BOOL32 bSTGM_READWRITE = ((openFlags & STGM_READWRITE) == STGM_READWRITE);
+  BOOL32 bSTGM_READ      = ! (bSTGM_WRITE || bSTGM_READWRITE);
+
+  if (bSTGM_READ)
+    flProtect = PAGE_READONLY;
+
+  if ((bSTGM_WRITE) || (bSTGM_READWRITE))
+    flProtect = PAGE_READWRITE;
+
+  return flProtect;
+}
+
+ 
diff --git a/ole/storage32.c b/ole/storage32.c
index 0a0887d7c13..4ea9da1a416 100644
--- a/ole/storage32.c
+++ b/ole/storage32.c
@@ -1866,7 +1866,12 @@ HRESULT Storage32Impl_Construct(
    */
   This->bigBlockSize   = DEF_BIG_BLOCK_SIZE;
   This->smallBlockSize = DEF_SMALL_BLOCK_SIZE;
-  This->bigBlockFile   = BIGBLOCKFILE_Construct(hFile, This->bigBlockSize);
+  This->bigBlockFile   = BIGBLOCKFILE_Construct(hFile,
+                                                openFlags,
+                                                This->bigBlockSize);
+
+  if (This->bigBlockFile == 0)
+    return E_FAIL;
  
   if (openFlags & STGM_CREATE)
   {
diff --git a/ole/storage32.h b/ole/storage32.h
index 1a196a2b034..c3803cab22c 100644
--- a/ole/storage32.h
+++ b/ole/storage32.h
@@ -138,6 +138,7 @@ struct BigBlockFile
   ULONG blocksize;
   HANDLE32 hfile;
   HANDLE32 hfilemap;
+  DWORD flProtect;
   MappedPage *headmap_ro;
   MappedPage *headmap_w;
   BigBlock *headblock;
@@ -147,7 +148,9 @@ struct BigBlockFile
  * Declaration of the functions used to manipulate the BigBlockFile
  * data structure.
  */
-BigBlockFile*  BIGBLOCKFILE_Construct(HANDLE32 hFile, ULONG blocksize);
+BigBlockFile*  BIGBLOCKFILE_Construct(HANDLE32 hFile,
+                                      DWORD openFlags,
+                                      ULONG blocksize);
 void           BIGBLOCKFILE_Destructor(LPBIGBLOCKFILE This);
 void*          BIGBLOCKFILE_GetBigBlock(LPBIGBLOCKFILE This, ULONG index);
 void*          BIGBLOCKFILE_GetROBigBlock(LPBIGBLOCKFILE This, ULONG index);