Could not save as because of a program error.

Adobe chat got me the answer. This is what they worked out in my situation.

"So sometimes when we use multiple monitors, our app considers one of our monitor as a Graphics Card and hence causes such issue, so as soon as we removed extra screen, Photoshop was able to detect correct Graphics Card and hence that issue got away, you may reconnect your screens and try again."

I unplugged my to external monitors from the main screen, restarted photoshop, then re-plugged in the monitors and files were saving again!

Any updates on this? It has been driving me insane. Starwhale said it was an external harddrive issue, but was also absolutely useless in telling us what that means.

Please let us know which program you are having problems with. Someone will be along to move this post to the appropriate product forum, where you are more likely to get an answer to your question.

The Using the Community forum is for help in using the Adobe Support Community forums, not for help with specific programs. Product questions should be posted in the associated product community.