The issue occurs when an External HDD or any other storage device is mounted or connected to the machine during the installation of File Encryption.
You can remove these drive letters of these partitions using mountvol command.
- Check Disk Management or Windows Explorer for what hidden partition should not be showing up.
- Right-click the Start button and click Command Prompt (Admin).
At the Command Prompt type the following then press Enter:
● mountvol E:\ /D
● mountvol F:\ /D
Click image to enlarge
- Close the command prompt.
- Restart the endpoint.
- Drive letter depends on the drive letter showing up in your Windows Explorer or Disk Management.
- Refer to the Microsoft Technet page for more information about Mountvol.