diff --git a/manifest b/manifest
index ed4a17e30f..d43ccc6be3 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Merge\saccidental\sfork.
-D 2013-04-01T17:58:10.824
+C In\swindows,\sround\sdown\sthe\ssize\sof\sthe\smemory\smapped\sregion\sto\sthe\snext\nsmaller\smultiple\sof\sthe\spage\ssize.
+D 2013-04-01T18:15:50.853
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in df3e48659d80e1b7765785d8d66c86b320f72cc7
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -161,7 +161,7 @@ F src/os.c 809d0707cec693e1b9b376ab229271ad74c3d35d
 F src/os.h ae08bcc5f6ec6b339f4a2adf3931bb88cc14c3e4
 F src/os_common.h 92815ed65f805560b66166e3583470ff94478f04
 F src/os_unix.c d136eca0cff2f8a5ac2f45867d5e5153d60e377c
-F src/os_win.c 390653f5c9b216bd445366f3c2b4863e52d51c24
+F src/os_win.c 4cb9b2621f4869e17c8caa627903dc114b1dfb37
 F src/pager.c 2b9980e87296812a6ce51121a3335550ae25e3ec
 F src/pager.h 5cb78b8e1adfd5451e600be7719f5a99d87ac3b1
 F src/parse.y 5d5e12772845805fdfeb889163516b84fbb9ae95
@@ -1040,7 +1040,7 @@ F tool/vdbe-compress.tcl f12c884766bd14277f4fcedcae07078011717381
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh fbc018d67fd7395f440c28f33ef0f94420226381
 F tool/win/sqlite.vsix 97894c2790eda7b5bce3cc79cb2a8ec2fde9b3ac
-P 4d67433db8fb4754ae6b192945e479f3d7bad579 ee4d188e207efa24a26776fa4f025c6ac39cce73
-R 5abed6f6d2f091dbf577966219204ad2
-U dan
-Z 994fbbedca554dbff615409d58ee1a84
+P 5f4437c0e35c8aa740515aac3e81e0146716d2bb
+R bde1c152af7414f4a8d87d63f33cdc11
+U drh
+Z 9887751c05c44b393c15dab1850774d3
diff --git a/manifest.uuid b/manifest.uuid
index 5c2360cd0a..91d9770506 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-5f4437c0e35c8aa740515aac3e81e0146716d2bb
\ No newline at end of file
+0e44ed1badde6d766f18d1373d968e5b286b15bd
\ No newline at end of file
diff --git a/src/os_win.c b/src/os_win.c
index 5ce5a4762a..6965ee90bb 100644
--- a/src/os_win.c
+++ b/src/os_win.c
@@ -3568,6 +3568,7 @@ static int winMapfile(winFile *pFd, sqlite3_int64 nByte){
   if( nMap>pFd->mmapLimit ){
     nMap = pFd->mmapLimit;
   }
+  nMap &= ~(sqlite3_int64)(winSysInfo.dwPageSize - 1);
  
   if( nMap==0 && pFd->mmapSize>0 ){
     winUnmapfile(pFd);