Index: src/os_win.c
==================================================================
--- src/os_win.c
+++ src/os_win.c
@@ -3893,11 +3893,11 @@
 **
 ** If the DMS cannot be locked because this is a readonly_shm=1
 ** connection and no other process already holds a lock, return
 ** SQLITE_READONLY_CANTINIT and set pShmNode->isUnlocked=1.
 */
-static int winLockSharedMemory(winFile *pDbFd, winShmNode *pShmNode){
+static int winLockSharedMemory(winShmNode *pShmNode){
   int lockType;
   int rc = SQLITE_OK;
 
   /* Use ReadFile/WriteFile to determine the locks other processes are
   ** holding on the DMS byte. If it indicates that another process is
@@ -4012,21 +4012,21 @@
     }
     if( rc2!=SQLITE_OK ){
       rc2 = winOpen(pDbFd->pVfs,
                     pShmNode->zFilename,
                     (sqlite3_file*)&pShmNode->hFile,
-                    SQLITE_OPEN_WAL|SQLITE_OPEN_READONLY|SQLITE_OPEN_CREATE,
+                    SQLITE_OPEN_WAL|SQLITE_OPEN_READONLY,
                     0);
       if( rc2!=SQLITE_OK ){
         rc = winLogError(SQLITE_CANTOPEN_BKPT, osGetLastError(),
                          "winOpenShm", pShmNode->zFilename);
         goto shm_open_err;
       }
       pShmNode->isReadonly = 1;
     }
 
-    rc = winLockSharedMemory(pDbFd, pShmNode);
+    rc = winLockSharedMemory(pShmNode);
     if( rc!=SQLITE_OK && rc!=SQLITE_READONLY_CANTINIT ) goto shm_open_err;
   }
 
   /* Make the new connection a child of the winShmNode */
   p->pShmNode = pShmNode;
@@ -4046,11 +4046,11 @@
   */
   sqlite3_mutex_enter(pShmNode->mutex);
   p->pNext = pShmNode->pFirst;
   pShmNode->pFirst = p;
   sqlite3_mutex_leave(pShmNode->mutex);
-  return SQLITE_OK;
+  return rc;
 
   /* Jump here on any error */
 shm_open_err:
   winShmSystemLock(pShmNode, WINSHM_UNLCK, WIN_SHM_DMS, 1);
   winShmPurge(pDbFd->pVfs, 0);      /* This call frees pShmNode if required */
@@ -4263,11 +4263,11 @@
   }
   pShmNode = pShm->pShmNode;
 
   sqlite3_mutex_enter(pShmNode->mutex);
   if( pShmNode->isUnlocked ){
-    rc = winLockSharedMemory(pDbFd, pShmNode);
+    rc = winLockSharedMemory(pShmNode);
     if( rc!=SQLITE_OK ) goto shmpage_out;
     pShmNode->isUnlocked = 0;
   }
   assert( szRegion==pShmNode->szRegion || pShmNode->nRegion==0 );