Could not complete your request File is not compatible with this version of Photoshop - Windows OS

Please help,

I've had this issue for a few months now, but initially it was just a file or two. I'm getting this notification for almost all of my files now, and it's causing issues throughout the suite (for instance, I cannot save an InDesign file to PDF because the Photoshop files contained therein are incompatible).  This is really frustrating!

I created these files in the same current version of Photoshop (sometimes minutes before receiving this error), I've checked to ensure that the software is up-to-date, and I'm working on a Toshiba laptop for work. I have deadlines to meet!

Thanks in advance for any and all assistance.

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