Geosammy's fix worked for me.

Note that the issue raised is NOT all temporary files. Rather, it is about temporary internet files.

Having the same problem, I want to subscribe to this thread but don't know how without first posting.

Having set up a POP3 email account within WIN 10 Preview, 10565, I'm unable to locate how to remove a received email from my provider's server. I'm prepared to hang my head in shame if it turns out...