Yeah, USB seems to be the nemesis of Windows since Windows 95, will that stuff ever work reliably 
? (Of course not.)
My Fairphone 2 all of a sudden stopped showing up as an MTP device in Explorer, although the connection was there.
Reinstalling the MTP driver helped for a while, before it stopped showing up again.
I now mainly mount the SD Card for Explorer. I only sync the Internal storage with MyPhoneExplorer anyway, and luckily that works without FP2 showing up in Explorer.