Note that the multi card format reader can also cause this issue if it isn’t external. Had the very same issue on a laptop with built-in SD slot, and had to go into the device manager and disable “Drives/Generic- Multi-Card USB Device” to make UE4 work.
Since it’s still a thing in UE4.15, it doesn’t seem to be very related to UE4 indeed, however most programs work just fine. I wonder what makes the difference…