I was working on a client’s PC, tuning it up, etc. The client mentioned that Quickbooks would always hang when posting a duplicate check. It turns out that the previous IT guy had disabled the sound card, since this was a “business computer”. Quickbooks was trying to generate an audible notice on a duplicate check and was not gracefully handling the fact that no sound card was available. I re-enabled the card, muted the sound, and quickbooks was happy again.