Walt, thanks for the responses to my post. I just tried to open a file using the "Open with" menu in the Windows 11 Photos app, just as depicted in your screenshot. The first time I got the error dialog I reported in my original post. The second time I tried it, I got a different dialog asking if I wanted to save a crash dump file. I declined and tried to open the file with the Photos app again. This time it worked. So there must have been a flag on opening files using this mechanism that cleared when AFPhoto2 detected the crash dump file. Long story short, it is now working as intended! Thanks again.