Have you seen this message? I've been seeing it lately in conjunction with middle mouse use and having my computer connected to a projector. I don't recall seeing it in other circumstances.
If you have I'd be curious what the circumstances have been (post a comment). I find that if I click Retry that I can at least save the file. Ultimately I have to click Abort and accept that RAC, RST or RME will have to close. At least I can save!!