Why do I get 'unidentified developer' error on documents

Sparkgapper wrote:

I just ported some old .jpg files over to Monterrey, changed them to open with my Paint app and get the 'Unidentified Developer' error. What is going on and how can I fix it?

sparkgapper

Ported...(?)

You moved some jpg files from where, over to Monterey ?

Was your Paint.app operational in both locations?

What was the default before(?) the Preview.app ?

Is this all on the same user account?

See if you need to add your Paint.app to the Full Disk Access folder in—

>System Preferences>Security & Privacy>Privacy

Controlling app access to files in macOS - Apple Support

Can you open you "Paint" app?