While copying photos from my iPhone to my Windows computer using File Explorer I received the error “A device attached to the system is not functioning” and then the copy fails. I Googled and tried the top 3 fixes suggested which were
1. Use a different USB port on my computer.
2. Use a different iPhone cable.
3. Try the copy on a different computer.
All of which gave the same error as before. The solution for me was on my iPhone go to Settings – Photos – scroll to the bottom and find
TRANSFER TO MAC OR PC – change from Automatic to Keep Originals.
After making that change I was able to copy all my photos over to my computer.