Windows 7: Program Compatibility Assistant query

I just encountered the Program Compatibility Assistant for the first time, but it was triggered by a Windows 7-compatible program. I'm concerned about the PCA's ability to block programs and I'm hoping that someone can tell me if there is a possibility that could happen as a result of a compatible, working program experiencing a crash, and if so how to ensure it doesn't and/or how to unblock software that's been mistakenly blocked.


More detail: Photoshop CS5 crashed on me yesterday. It's fully compatible with Win 7 and has been working fine on this PC for months (although I was entering my printer settings again at the time of the crash--since migrating to this PC it occasionally forgets them, something I suspect is more to do with the ageing printer than the software), but after clicking the close program dialog box I got a PCA box informing me that compatibility changes had been applied to the Photoshop .exe file. No options were presented to me. I checked out the PCA in Help and saw that it has the ability to block software that it identifies as problematic. Is it likely that Photoshop could be blocked by Windows if it ever crashes or glitches again, or is that measure only applied in other types of cases?

PCA don't blocks programs, but instead changes its compatibility settings in an attempt to make them work with Windows 7. In your case, triggering it may be just a "false positive" due to the crash (PCA guessing that it crashed because of Windows 7, instead of a bug in the program). Just ignore it, and say it worked correctly if ever asked again. If you've touched any settings or let PCA to apply its changes at will, go to the compatibility tab of the main executable and disable compatibility mode.

Personally, I always disable PCA, as it only creates more problems than it solves and a lot of annoying popups. I have yet to see it correctly fixing a program.

Program Compatibility Assistant - Enable or Disable

Thanks, that's good to know. It didn't ask me anything or give me the option to not apply settings, just informed me that it had made the changes, but as compatibility mode is unchecked for the .exe file I don't know what it actually did.

One more question: is it okay to disable PCA after it has applied compatibility settings to a program? If I needed to, would I still be able to undo them with it disabled?

Yes, there will be no problem in undoing any changes it does. The only thing it touches is the compatibility tab, and you're able to change it at will.
If nothing seems changed there, my guess is that it's applying something for a one-time only and not saving a configuration. If so, there would be nothing to undo really.

Great, thank you for the help!