diff --git a/Source/NSCalendarDate.m b/Source/NSCalendarDate.m
index f4a880a0d..586281291 100644
--- a/Source/NSCalendarDate.m
+++ b/Source/NSCalendarDate.m
@@ -1689,9 +1689,12 @@ static inline int getDigits(const char *from, char *to, int limit)
    */
   if ([date isKindOfClass: [NSCalendarDate class]])
     tmp = (NSCalendarDate*)RETAIN(date);
-  else
+  else if ([date isKindOfClass: [NSDate class]])
     tmp = [[NSCalendarDate alloc] initWithTimeIntervalSinceReferenceDate:
 		[date timeIntervalSinceReferenceDate]];
+  else
+    [NSException raise: NSInvalidArgumentException
+		format: @"%@ invalid date given", NSStringFromSelector(_cmd)];
 
   end = (NSCalendarDate*)[self laterDate: tmp];
   if (end == self)
diff --git a/Source/NSUserDefaults.m b/Source/NSUserDefaults.m
index 2c47ac041..18389d9a4 100644
--- a/Source/NSUserDefaults.m
+++ b/Source/NSUserDefaults.m
@@ -219,6 +219,7 @@ static BOOL setSharedDefaults = NO;	/* Flag to prevent infinite recursion */
     {
       NSDictionary	*regDefs;
 
+      [sharedDefaults synchronize];	// Ensure changes are written.
       regDefs = RETAIN([sharedDefaults->_tempDomains
 	objectForKey: NSRegistrationDomain]);
       setSharedDefaults = NO;