you may have run in to an issue that has plagued windows from the beginning of time.
shlemiel the painter
windows explorer cannot handle accessing a folder that contains more than a certain number of files. I don't remember how many, but it is MORE than 65000.
I ran in to this during the infamous "microsoft updating windows 7 to 10 without warning" fiasco of several years ago.
my mother-in-laws computer rebooted and started installing windows and hung up for several days. not wanting to screw up whatever was going wrong I waited and after almost a week it finished the install. she did not want windows 10 so I reversed the process which also took a week.
when it finished I was going though her computer and found a folder that when I tried to access it explorer hung up/froze or something like that. I narrowed it down to a folder (I forgot where but not the TEMP folder) that had over 2,000,000 very small files in it. I don't know the exact amount because trying to get a DIR never completed even after several hours. attempts to right click on the folder and get it's properties also hung everything up. I tried running a delete command in the folder and after several hours (and several tries) it did not complete and was excruciatingly slow.
I ended up using a robocopy command to mirror an empty folder to that clogged folder which basically deleted everything in it. it took almost a day and ended with something over 2 million files deleted.
I have no idea where the files came from.
a friend of mine accidentally did something similar when he wrote a batch file to create a folder that accidentally recursively created the same folder as a sub folder several thousand times. that required a special program to clean up the mess.