View Mounted Drive Letters in Windows Registry

Windows stores system-wide drive letter assignments and volume mapping information—including those used by encrypted drives like BitLocker or mounted container files—directly inside the Registry. This guide explains the exact location within the Registry Editor (regedit) where you can view assigned drive letters, match them to their unique Volume GUIDs, and inspect persistent mount configurations.

The Registry Path for Mounted Drive Letters

The primary location for all assigned drive letters and mounted volumes in the Windows Registry is:

HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices

How to View the Drive Letters

1. Press Windows Key + R, type regedit, and press Enter to open the Registry Editor.
2. In the left navigation pane, expand the folders to navigate to: HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices
3. Look at the Name column on the right side.

Understanding the Registry Values

In the MountedDevices key, you will see two primary types of entries:

• \DosDevices\[DriveLetter]: (e.g., \DosDevices\C:, \DosDevices\E:): These entries represent the drive letters currently or previously assigned to storage volumes on the system.
• \??\Volume{GUID}: These entries represent the unique globally unique identifiers (GUIDs) assigned to specific physical partitions, encrypted partitions, or virtual volumes.

Identifying Encrypted Volumes

• Matching Drive Letters to Volumes: The binary data stored in each \DosDevices\[DriveLetter]: value directly corresponds to the binary data of one of the \??\Volume{GUID} entries. By comparing the binary data, you can determine which specific volume GUID is mapped to which drive letter.
• BitLocker Drives: When a BitLocker volume is unlocked and mounted, Windows binds it through this standard storage subsystem, meaning its assigned drive letter appears under \DosDevices\ mapped to the volume’s underlying partition signature.
• Third-Party Encrypted Volumes (VeraCrypt, TrueCrypt): Third-party encryption tools that mount virtual containers as standard Windows drive letters also register the temporary DOS device name mappings in this key or link directly into the Windows mount manager for the duration of the active mount session.