while we have had some reports of crashes, nobody has reported a crash on closing so far.
Is the “quick launch” option enabled in help->options->general?
This will send the PDF Architect to the background instead of actually closing it and might be connected to the issue, please check if disabling it solves the problem.
Sorry for the trouble.
I agree it is a similar problem, but for the other users it seems to be happening at random times, while in your case, if I understood correctly, it only happens when they close the application? Are any PDF Architect related errors logged in the Windows event log? If yes, please post the error messages here which will help us to troubleshoot thr problem more efficiently.