With Gedcom sync off, the Check Gedcom link (Manage Gedcoms page) emits a bright red warning that the Gedcom is not in sync. This unintentionally confers the message that a serious error exists, especially since the user clicked the link to check for errors. If PGV is moving towards unsynced Gedcoms then this should be fixed, since it is an obstacle to that move.
Also, Check Gedcom runs out of memory or time on many installations, independent of sync turned on or off.
This is in some cases functionally related to bug 3014255, which relates to upload/replacement of Gedcoms. These two errors in tandem would be very confusing.
Suggested improvement choices:
(easy) Instead of a scary warning, display a message box offering the genealogist an option to sync the Gedcom before checking.
(better) Check the database instead of the Gedcom. Should be faster and less memory intensive and better supports unsynced operation, but would probably require significant new code. Optionally, a gedcom file check could be retained as a utility.