Veeam Backup Error - 'Unable to release guest. Error: Unfreeze error

Veeam Backup Error - 'Unable to release guest. Error: Unfreeze error:'

Problem

Yesterday morning, I walked into the office, the boss told me a client's Exchange was running slowly and they had had a Veeam backup fail. I know this client well enough to know if it was something simple he would have fixed it himself, so while my laptop booted I armed myself with a coffee.

I connected to the Veeam backup server and this was the error.

Unable to release guest. Error: Unfreeze error: [Backup job failed. Cannot create a shadow copy of the volumes containing writer's data. A VSS critical writer has failed. Writer name: [Microsoft Exchange Writer]. Class ID: [{76fe1ac4-15f7-4bcd-987e-8e1acb462fb7}]. Instance ID: [{65ec880f-7b6a-402f-baf1-14d4de7f6fb9}]. Writer's state: [VSS_WS_FAILED_AT_FREEZE]. Error code: [0x800423f2].]
Error: Unfreeze error: [Backup job failed. Cannot create a shadow copy of the volumes containing writer's data. A VSS critical writer has failed. Writer name: [Microsoft Exchange Writer]. Class ID: [{76fe1ac4-15f7-4bcd-987e-8e1acb462fb7}]. Instance ID: [{65ec880f-7b6a-402f-baf1-14d4de7f6fb9}]. Writer's state: [VSS_WS_FAILED_AT_FREEZE]. Error code: [0x800423f2].]

Solution

1. OK that’s a huge error, but essentially it's complaining about the VSS writer on the Exchange server. Log onto the Exchange server, drop to command line and issue the following command;

vssadmin list writers

Chances are you will see the following;

If you look in the Event Log you will probably also see Event ID 2007.

Information Store (2544) Shadow copy instance 1 aborted.

2. To fix that you need to restart the Microsoft Exchange information store service.

3. Check again to make sure you are back up.

4. Note: We are backing up using Veeam, make sure there is no instance of the Symantec Backup Exec Remote Agent for Exchange, if it's there remove it.

5. Finally, I’ve got over 120GB of transaction logs to contend with, for the problem mail store, I’m going to enable circular logging to free up some room. (Note: You can disable this again once you have a decent backup if you wish).

6. At this point I rebooted both the Exchange server and the Veeam Backup server it then performed a backup of the Exchange server without error.