Hi Everone
I've been working with one of our users on a similar issue.
The User is reporting that when he transfers the files from his iPhone (iOS 14.7) currently to his Windows 10 laptop the file becomes corrupt and is unable to open. Not sure if this is what your seeing, but here's where we are at so far.
1) He is not using iCloud or iTunes. Rather he is transfering them directly using Windows Explorer. We would perfer not to use iTunes or iCloud since these photos are confidential and all we need is to sync photos.
2) The photos seem to work fine the first time he transfers data. However when he disconnects the phone from the computer, then they stop working.
3) He is able to email the photos to others and then have them email the photos back to him. These photos work. Right now he is going to email the photos to himself, but I suspect this will work.
4) The photos are all *.jpg files. None of these photos are the *.heic files, which on Windows 10 is a headache for another time.
What this is leading me to believe is that the phone is encrypting the photos. I'm not sure if there is a way to decrypt the iPhone temporaraly to test this theory. But if nothing else, this might provide some clues as to what could be happening.