My Windows 10 machine started behaving weirdly and did not mount any USB Drives / Harddrives and such anymore. I had to open the Disk Management Tool and mount them manually, which is quite inconvenient. So I was looking up the error and came across the nearly perfect solution at http://woshub.com/windows-doesnt-assign-letters-to-external-and-usb-flash-drives/ . However, I did change it a bit so that the VDS is changed to automatically start on boot via the CLI :).
Oh, and yes, you need to do this from an admin cmd 😉
First thing to check if something is wrong, is if your VDS (Virtual Disk Service) works. If not, set it to start on boot and start the service:
sc query vds sc config vds start= auto sc start vds sc query vds
If automounting still not works, it could be deactivated. Start diskpart, watch the status of automount and if it is disabled, activate it.
diskpart DISKPART> automount DISKPART> automount enable DISKPART> exit