Windows: Space Remains Allocated After Turning Off Shadow Copies

Windows creates shadow copies which are snaphots of the volume at the time the copy was taken. Shadow copies consume relatively little space as they essentially capture incremental changes.

After turning off shadow copies on a volume, some space may still show as allocated, even if the volume seems to be empty:

In the above, H: is empty. Additionally the shadow copies dialog shows space occupied:

If you attempt to clear the shadow copies manually:

vssadmin delete shadows /for=H: /all

You receive: Error: Snapshots were found, but they were outside of your allowed context. Try removing them with the backup application which created them.

This occurs because snapshots can be created by various applications, not just Windows. The most common example is the Windows Server Backup tool. When turning off shadow copies via Explorer, only the shadows created by Windows are removed. What remains are shadows created by other applications.

To remove all shadows:

1. Open an elevated command prompt.

2. Type:

   Diskshadow

3. Type:

   delete shadows volume H:

   (Where H: is the volume in question)

   All the shadows should be removed.

4. Type:

   exit