Invalid or corrupt project - HELP!

I've had this issue a lot as well and so have started backing up my working files.

For me it seems to occur when sharing files over our company's network. I'll place a file in a network folder location and a colleague will download it - but will be unable to work on it due to this error message. We all have the latest update, the file naming conventions are in line with our corporate standard (meant to be more stringent than the 260 character limit, no special characters etc.) and we generally don't do anything too wild with the files themselves. Our network is stable and seems to work well when sharing anything else.

Recently, while trying to open up one of these corrupted monstrosities sent to me by a coworker, I had the bright idea to try to import the slides into a new file. The attached error message resulted. I hope this helps with diagnosing the problem, Articulate folks!