Windows Server Backup Fails with Event ID: 521 “There is not enough disk space to create the volume shadow copy on the storage location.”

Log Name: Application
Source: Microsoft-Windows-Backup
Date: 7/15/2016 4:44:09 PM
Event ID: 521
Task Category: None
Level: Error
Computer: server1
The backup operation that started at ‘‎2016‎-‎07‎-‎15T20:44:03.429000000Z’ has failed because the Volume Shadow Copy Service operation to create a shadow copy of the volumes being backed up failed with following error code ‘2155348249’. Please review the event details for a solution, and then rerun the backup operation once the issue is resolved.

This failure happens when Volume Shadow Service (VSS) does not have enough disk space to create a snapshot of the data being backed up. All you have to do is figure out which drive does not have enough free space. Here is how you find the disk in question and resolve it.

1. Open Windows Server Backup

2. Click “View Details” in the Status section for the Last Backup


3. Click the Errors tab and look for the Message “The operation was stopped. Detailed error: The volume shadow copy operation failed with error 0x8004231F. View the event log for more information.” This will be the drive that needs to have shadow space freed up. If the error is on “System state” you will have to free up space on the “System Reserved” disk. The the “System Reserved” is a special disk used for booting up your system so instead of freeing up space on the “System Reserved” disk and possibly winding up in a no boot situation the I recommend changing the location of the shadow storage for “System Reserved” to another disk like C. NOTE: the shadows for the “System Reserved” are very small (2008r2=100MB max, 2012=350MB max, 2012r2=500MB max).


4. Open Disk Management(DISKMGMT.MSC)

5. Right click “System Reserved” and select Properties

6. Click the Shadow Copies tab

7. Click the Settings button

8. Click the drop-down arrow, select C:\ and click OK and OK




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