I noticed some other people have had similar problems and one even looks like they used a solution similar to what I was provided with from Symantec. However, after resolving an issue with backups failing due to VSS issues, the problem seems to have returned. Initially I was getting VSS errors in BackupExec 12.5 which was causing the Exchange 2010 backups to either fail late in the process or fail alltogether. When we checked vssadmin list writers and saw we had some writers missing, we were provided with a batch file to re register the writers. After running this and rebooting all 3 mailbox servers, the backups ran for about a week. Today I got an alert that the Exchange Differential backup failed with a VSS error, so I checked the vssadmin list writer again on all 3 servers and sure enough the Microsoft Exchange Replica Writer is missing on one. Also, the BITS Writer is missing on this server too. I know I can rerun this batch file and reboot to resolve this, but what I need is why to prevent this from happening to begin with.

Hi, What is the OS of your Exchange Server? Hyper-v? Do you have DAG created? Please understand that If a server hosting the data being backed up is a member of a database availability group (DAG) and hosts both active and passive database copies, you must disable the Microsoft Exchange Replication service VSS writer. Also you can run "vssadmin list writers" from a command prompt. Xiu Zhang TechNet Community Support

We are running Windows Server 2008 Enterprise R2. No, we are not using virtual servers for our Exchange environment. Yes, we have a DAG consisting of 3 mailbox servers. None of our servers are hosting both copies. Each of our databases is hosted on two of the servers with the database mounted on one and a copy on the other. This setup should alleviate the requirement to disble Microsoft Exchange Replication service VSS writer. Also, running "vssadmin list writers" from a command prompt is how I know that, as stated originally, the Microsoft Exchange Replica Writer is missing again from one of the mailbox servers. Finally just to provide provide updates, a Exchange Full backup job completed without error after the Exchange Differential job that failed after the fix from Symantec.

Hi, Please understand that the Replication Writer is available on the passive node of DAG server. Backup issues and limitations with Exchange 2010 and DAG http://blogs.technet.com/b/ehlro/archive/2010/02/13/backup-issues-and-limitations-with-exchange-2010-and-dag.aspx By the way, what is the detail VSS error when you perform differential backup?Xiu Zhang TechNet Community Support

In regards to the Replication Writer being on the passive nodes, my 3 main mailbox servers all host active and passive databases. Also, I keep forgetting about a CAS/Mailbox server we have at a remote site. This server actually seems to be the problem at the moment. It is hosting an active copy of RadioLocal database which is in the error information below. This server has a retryable error on its replication writer and the replication writer is missing all together from the server that is hosting the passive copy. Ok, so after a successful Full Backup, the following Differenial Backup failed after processing about 480 GB of data. Also, the full backup was set to use active copy for testing with Symantec while the differential is still set to I believe automatically choose. The error is as follows. Backup- SPMCAS03 V-79-57344-65233 - AOFO: Initialization failure on: "\\EWTNDAG\Microsoft Information Store\RadioLocal". Advanced Open File Option used: Microsoft Volume Shadow Copy Service (VSS). Snapshot provider error (0xE000FED1): A failure occurred querying the Writer status. Check the Windows Event Viewer for details. Writer Name: Exchange Server, Writer ID: {76FE1AC4-15F7-4BCD-987E-8E1ACB462FB7}, Last error: The VSS Writer failed, but the operation can be retried (0x800423f3), State: Failed during prepare backup operation (7). I am going to try to run the symantec provided fix on the remote server hosting radiolocal and reboot, but I am still concerned about why the replication writer was on all servers after fix/reboot but has dissappeared from one.

Hi, If we host active and passive database together on one database server, then we need to disable Replication Writer. Please check the issue and update here after you have fix the symantec problem. Xiu Zhang TechNet Community Support

Besides, when you use a different a backup solution to back up passive database copies on a server that has the Microsoft Exchange Replication service VSS writer disabled, you need to remove the preceding registry key and then restart the Microsoft Exchange Replication service. So please check the status of your replication VSS writer from HKEY_LOCAL_MACHINE\Software\Microsoft\ExchangeServer\v14\Replay\Parameters. If you have 0 as value on EnableVSSWriter, then it indicates that we have disable VSS writer. Using Windows Server Backup to Back Up and Restore Exchange Data http://technet.microsoft.com/en-us/library/dd876851.aspxXiu Zhang TechNet Community Support

Besides, when you use a different a backup solution to back up passive database copies on a server that has the Microsoft Exchange Replication service VSS writer disabled, you need to remove the preceding registry key and then restart the Microsoft Exchange Replication service. So please check the status of your replication VSS writer from HKEY_LOCAL_MACHINE\Software\Microsoft\ExchangeServer\v14\Replay\Parameters. If you have 0 as value on EnableVSSWriter, then it indicates that we have disable VSS writer. Using Windows Server Backup to Back Up and Restore Exchange Data http://technet.microsoft.com/en-us/library/dd876851.aspxXiu Zhang TechNet Community Support

The server in question does not have this registry key, so I am guessing it is enabled by default. Currently though I have two conflicting positions on this. Symantec tells me that this writer must be enabled and running or Backup Exec will not backup the Exchange database...which has been observed to be the case. However, here I am told to disble this writer. Regardless of either, the original solution I was requesting has not even been discussed. How do I prevent this writer from going offline or dissappearing from the writer list?

Hi, How is the issue now?Xiu Zhang TechNet Community Support

Well, I have my exchange backups running again, but otherwise still no resolution on preventing the writer from dissappearing from the servers.