diff --git a/UAAppReviewManager.m b/UAAppReviewManager.m
index 952c67e..2e6dffc 100644
--- a/UAAppReviewManager.m
+++ b/UAAppReviewManager.m
@@ -578,7 +578,7 @@ - (void)_incrementCountForKey:(NSString *)incrementKey {
 	NSString *currentVersionKey = [self keyForUAAppReviewManagerKeyType:UAAppReviewManagerKeyCurrentVersion];
 	NSString *trackingVersion = [self.userDefaultsObject objectForKey:currentVersionKey];
 	// New install, or changed keys
-	if (!trackingVersion) {
+	if (!trackingVersion || ![trackingVersion isKindOfClass:[NSString class]]) {
 		trackingVersion = currentVersion;
 		[self.userDefaultsObject setObject:currentVersion forKey:currentVersionKey];
 	}