diff -up blender-2.63a/source/blender/blenkernel/intern/blender.c.cve blender-2.63a/source/blender/blenkernel/intern/blender.c
--- blender-2.63a/source/blender/blenkernel/intern/blender.c.cve	2012-05-10 16:50:20.000000000 +0200
+++ blender-2.63a/source/blender/blenkernel/intern/blender.c	2012-09-07 10:10:05.518999947 +0200
@@ -40,6 +40,7 @@
 #  define write _write
 #endif
 
+#include <errno.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <stddef.h>
@@ -706,7 +707,8 @@ void BKE_undo_save_quit(void)
 {
 	UndoElem *uel;
 	MemFileChunk *chunk;
-	int file;
+	int file = -1;
+	int flags = O_BINARY+O_WRONLY+O_CREAT+O_TRUNC;
 	char str[FILE_MAX];
 	
 	if ( (U.uiflag & USER_GLOBALUNDO)==0) return;
@@ -722,10 +724,16 @@ void BKE_undo_save_quit(void)
 		
 	BLI_make_file_string("/", str, BLI_temporary_dir(), "quit.blend");
 
-	file = BLI_open(str,O_BINARY+O_WRONLY+O_CREAT+O_TRUNC, 0666);
-	if (file == -1) {
-		//XXX error("Unable to save %s, check you have permissions", str);
-		return;
+	while (file == -1) {
+	  file = BLI_open(str,flags, 0666);
+	  if (file == -1) {
+	    if (errno == EEXIST) { 
+	      flags ^= O_CREAT;
+	    } else {
+	      //XXX error("Unable to save %s, check you have permissions", str);
+	      return;
+	    }
+	  }
 	}
 
 	chunk= uel->memfile.chunks.first;