OK, I wouldn't leave it to mystify me. The clue is that when you reboot it kicks in.
When time permits, enable the device and then perform a clean boot. Then step by step try to find out which service/ startup is trying to kick up the drive. May be you will find the culprit.
It would be interesting to run Partition Wizard (or other similar Linux based program) to see what it shows.
Its a USB device or so Windows thinks. If I delete it, when I reboot and Windows starts it detects it and installs it. However, as there is no physical device ???
There are no unknown devices listed in the USB section of Device Manager.
Did you Show hidden devices in Device Manager and see if anything odd is listed there?
How about a printer?
I have an all-in-one printer that has a USB port and whether it has anything plugged into it or not it shows up on my system as another disk. Disk 3 in Disk Management with "No Media" label.
Any chance it is something similar?
No virtual machines. Very "vanilla" system since I use it for my recording studio, and as I've previously noted the same thing in Win 8.1 (dual boot system). The drive is listed in the Device Manager, under Disk Drives as "USB Device".
It would seem to be something on the motherboard or BIOS since both OS' have the same thing. The BIOS has not been changed (its a 2012 BIOS the last one ASRock issued for this Z77 motherboard) so that would seem to eliminate it. No USB device is being detected by the BIOS that I can see.
Yeah this is very strange, I'll carry on doing some digging to see if I can find anything out.
In your case Disk 4 is shown as Removable M:, No Media . It also has a drive letter M. (It is not the same as fireberd's problem.)
So it could be a Card Reader, Printer with a card Reader, or any other USB connected device that may have escaped your attention. :)
If you are sure that you have none of it, then be sure to disconnect any and all USB connected devices from the front and rear USB ports. Physically check it. No other USB connected USB port plugged in devices except your USB Keyboard and USB mouse. Disconnect your network too so that you do not see any network connected device .
Then run the drive cleanup as in my post #14.
Reboot and check whether your stuck M: drive gets released.
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