When you are facing “non-auto-assigning Drive Letter” issue using external card readers & USB Flash Drives, perform the below to solve the issue.
Making sure that the Virtual Disk service is running. You can check the status of this service in the services management console (services.msc).
This is how to do that:
Go to <Computer Management>
Click on <Services> Tab
Browse the list appeared for <Virtual Disk> and Double Click on it
Making sure the “Service Status” shows “Running” & all START, PAUSE & RESUME buttons are dimmed. If “Service Status” showing as “Stopped”, CLICK ON THE “START” button.
Restart your computer and try it again, the systems should now be able to auto-detect / auto-assign drive letters to all external card readers or drives.
For more of the same topic, you may also visit: http://woshub.com/windows-doesnt-assign-letters-to-external-and-usb-flash-drives/?fbclid=IwAR09U0l0I7yK5S5IhAew8Q-PjHgFplQjlHKLivX01nX2Bn0A8pWip68FUUA