diff --git a/Sparkle/SUUpdater.m b/Sparkle/SUUpdater.m
index 8eb95a5f..3aa21754 100644
--- a/Sparkle/SUUpdater.m
+++ b/Sparkle/SUUpdater.m
@@ -170,6 +170,8 @@ - (void)scheduleNextUpdateCheck
 
 - (void)checkForUpdatesInBackground
 {
+	checkTimer = nil; // Timer doesn't repeat, so it's invalid, just needs to be set to nil.
+	
 	[self checkForUpdatesWithDriver:[[[([self automaticallyDownloadsUpdates] ? [SUAutomaticUpdateDriver class] : [SUScheduledUpdateDriver class]) alloc] initWithUpdater:self] autorelease]];
 }