From what I can tell, it seems to be a memory thing - and is more prevalent in recent firmware, or perhaps I’m just printing much larger prints lately. Usually my prints don’t exceed 6 hours, and lately I’m doing all-day prints, so while in the past I could hit 20 pages of files, it was coming in at about 3 pages this time.
Anyway, it will freeze up every time if you try to delete anything. First start with clearing history, and keep doing that a few times until all the history is gone… Then restart the printer, and try to delete the smallest file you can find. That worked for me to get around the freeze problem when deleting.
Oh, I should add, clearing history and deleting files are two completely different things. I’m not sure what delete history actually does, since it leaves the files there, but I found it had to be done before I could delete any files themselves. Files must be deleted one by one by opening the file and manually deleting it. There’s no group-delete function.
After I did that, I was able to print again.
This happened to me twice, so seems consistent.