How To Resolve an 'Insufficient Storage Space' Error

VSS (Volume Shadow Copy Service) is a feature within the Microsoft Windows OS (operating system) that allows applications to take a "point-in-time snapshot" of an entire storage volume without locking the filesystem. If there is not enough free space in the VSS storage, a backup may fail with the following error:

"The system or provider has insufficient storage space. If possible delete any old or unnecessary persistent shadow copies and try again."

In this article, we will walk through adjusting the VSS storage to resolve the error.

Step 1 – Verifying VSS Storage Allocation

Click the Start menu button (i.e., the Windows flag icon in the lower-left corner)

Type "cmd" to search for the Command Prompt application.

Right-click on Command Prompt and select the Run as administrator option:

Check the size of the Shadow Copy Storage with the 'vssadmin' command:

C:\> vssadmin list shadowstorage

Note: For additional information about the command used above, please review the Vssadmin list shadowstorage article from Microsoft.

Sample Output:

vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
(C) Copyright 2001-2013 Microsoft Corp.

Shadow Copy Storage association
   For volume: (C:)\\?\Volume{55ce9f76-2c16-4b08-b03a-621373750a9d}\
   Shadow Copy Storage volume: (C:)\\?\Volume{55ce9f76-2c16-4b08-b03a-621373750a9d}\
   Used Shadow Copy Storage space: 10.2 GB (9%)
   Allocated Shadow Copy Storage space: 10.7 GB (9%)
   Maximum Shadow Copy Storage space: 11.1 GB (10%)

Note: The number of disks, their names, and the amount of free space on your system will vary from the output above.

In this particular scenario, the output shows that the shadow storage is full. Two approaches, expanding or deleting, exist to resolve the situation, see steps 2.1 and 2.2, respectively, for instructions.

Step 2.1 – Expanding Shadow Storage

Expand the Maximum Shadow Copy Storage with the 'vssadmin' command:

C:\> vssadmin resize shadowstorage /For=C: /On=C: /MaxSize=UNBOUNDED

Note: Set the drive letter (e.g., C:) to the Shadow Copy Storage volume on your system.
Also, for additional information about the command used above, please review the vssadmin resize shadowstorage article from Microsoft.

Sample Output:

vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
(C) Copyright 2001-2013 Microsoft Corp.

Successfully resized the shadow copy storage association

Verify the expansion with the 'vssadmin' command:

C:\> vssadmin list shadowstorage

Sample Output:

vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
(C) Copyright 2001-2013 Microsoft Corp.

Shadow Copy Storage association
   For volume: (C:)\\?\Volume{55ce9f76-2c16-4b08-b03a-621373750a9d}\
   Shadow Copy Storage volume: (C:)\\?\Volume{55ce9f76-2c16-4b08-b03a-621373750a9d}\
   Used Shadow Copy Storage space: 10.2 GB (9%)
   Allocated Shadow Copy Storage space: 10.7 GB (9%)
   Maximum Shadow Copy Storage space: UNBOUNDED (3623414811%)

Step 2.2 – Deleting Shadow Storage

Warning: This approach is NOT recommended and should only be used if step 2.1 fails to resolve the issue.

Delete the Shadow Copy Storage with the 'vssadmin' command:

C:\> vssadmin delete shadows /for=C: /all

Note: Set the drive letter (e.g., C:) to the Shadow Copy Storage volume on your system.
Also, for additional information about the command used above, please review the vssadmin delete shadowstorage article from Microsoft.

Sample Output:

vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
(C) Copyright 2001-2013 Microsoft Corp.

Successfully resized the shadow copy storage association

Verify the expansion with the 'vssadmin' command:

C:\> vssadmin list shadowstorage

Sample Output:

vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
(C) Copyright 2001-2013 Microsoft Corp.

Do you really want to delete [X] shadow copies (Y/N): [N]? y

Successfully deleted [X] shadow copies.

Verify the deletion with the 'vssadmin' command:

C:\> vssadmin list shadowstorage

Sample Output:

vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
(C) Copyright 2001-2013 Microsoft Corp.

Shadow Copy Storage association
   For volume: (C:)\\?\Volume{55ce9f76-2c16-4b08-b03a-621373750a9d}\
   Shadow Copy Storage volume: (C:)\\?\Volume{55ce9f76-2c16-4b08-b03a-621373750a9d}\
   Used Shadow Copy Storage space: 0 bytes (0%)
   Allocated Shadow Copy Storage space: 0 bytes (0%)
   Maximum Shadow Copy Storage space: UNBOUNDED (3623414811%)

Conclusion

There you have it! After adjusting the Shadow Copy Storage volume, perform a backup without the "insufficient storage space" error.