This morning I had 415 MB worth of them in that folder. Every day I have large amount of the these folders in my Temp folder.
What program is putting them there? Everyday I use CCleaner to clean them out.
Probably related to a Cloud account or Backup drive. I discovered source of MEI Folders by expanding into subfolders until I spotted some image files all used in Google Cloud interface - had 20 MEI folders in TEMP (30+Mb each). Appears that (1) MEI Folder was being generated each time GOOGLE Cloud did a sync - which I had set-up to do at startup. I changed to manual sync and the MEI's Folders stopped. FYI, I fould it OK to delete MEI's, but do your own research. Might be good to leave most current.