Downloading photos from iCloud to Mac

mbither wrote: I am downloading full resolution photos from iCloud to Mac to repopulate the full versions on my Mac. Suddenly after a short time the download has stopped. Please help!

How large are the batches of pictures you are trying to download a once? You're much more likely to run into a glitch somewhere in a large batch than in a smaller one. Video is more likely to be problematic than a photo-- can narrow down which pictures might have caused the interruption?

And, of course, how is your internet, and how about your storage space? If you are using an external drive, then it will work better if it is formatted in either APFS format or Mac OS Extended (Journaled) format. And, if you want to run a Photos Library on an external drive, it must be formatted in one of these.