SharePoint 2007 Backup Failed - Cannot open backup device

You may have seen this error Error: Object SharePoint_Config failed in event OnBackup. For more information, see the error log located in the backup directory. SqlException: Cannot open backup device '\\servername\backup\spbr0001\0000001.bak'. Operating system error 5(error not found).

After reading this article http://technet2.microsoft.com/Office/en-us/library/b4dfe06a-40a5-4826-8d4b-1d758a9e621a1033.mspx?mfr=true I resolved the issue. The steps I took were:

• Set the SQL Server (MSSQLSERVER) Windows service to run as a domain account. Will require a restart of the service and IIS.
• Setup sharing on the backup folder. Grant access for the identity that the Central Administration Application Pool runs under, the database SQL account, the identity that the Timer service runs under, to change and read rights.
• On each of the SharePoint servers check you can access the share.
• On each of the database servers check you can access the share.
• Set the folder security, grant privledges for the identity that the Central Administration Application Pool runs under, the database SQL account, the identity that the Timer service runs under to all rights apart from Full Control.

This will fix backups that are performed using SharePoint 2007 Central Administration.

If you are running backups from STSADM you will need to grant access to the share and write access to the folder security for the user that runs the STSADM -o backup command.