SQL Backups failing with error 'MSDEWriter' is configured as the default writer for SQL Server instead of the 'SqlServerWriter'


When running SQL backups or inventory sync getting error in WBPS logs about MSDEWriter being set as default


MSDEWriter is being used by SQL instead of SQL VSS Writer and an error is reported in the backup messages stating this must be corrected.  

FIRST: verify all permissions have been correctly configured per KB 3104, no spaces have been found in database names, and the SQL VSS Writer is still not showing when running vssadmin list writers.  If so this condition may be present and you may need to force Windows to use the correct writer during backup calls. 

This is a rare condition usually created by installing multiple applications on the same server that are not intended to be cross compatible with SQL installations, but can also indicate corrupt SQL installations, or may be seen on some 2005 SQL editions.  


Note: Changing the below noted registry key is not recommended by Unitrends without consultation of your 3rd party app vendor or Microsoft Support.   Unitrends can participate on calls with your vendor in such cases for customers with currently active support agreements.  Making this change is at your own risk, but may result in successful VSS backups.  Without an understanding of why this setting is not already present in windows, it is ill advised to be changed as it may cause improper response of other applications.  This information is provided as a reference only and not as a recommendation.

Open the registry editor and locate the registry key:


Make a backup copy of the key before changing it.  

Set the DWORD entry(or create it if it does not exist) MSDEVersionChecking and set it to 1.


Windows is defaulting to the incorrect VSS Writer, MSDEWriter and is not using the proper SQL VSS writer which is a requirement for VSS backups used by Unitrends and most other vendors on modern servers.  This is not a Unitrends issue but is a SQL configuration fault that prevents the use of VSS.  

This may happen on 2005 or MSDE editions of SQL and is the expected setting in those editions, requiring use of the legacy SQL backup agent instead of VSS or VDI aware backups supported in later SQL editions.  Note the legacy SQL agent is depreciated by Unitrends but is the only supported method to protect MSDE and SQL 2000 or some 2005 editions.  Servers in this configuration are recommended to be updated to SQL 2008 standard or higher to avoid the requirement of using depreciated code.  

This setting may also be present due to improper deployment of an application that leverages the WID (Windows Internal Database) on a server that also has SQL installed.  For example, if SCCM or WSUS is installed on a SQL server and was NOT specifically set to use SQL as it's database using an additional SQL instance but instead was deployed using the default WID or express database configuration then this condition may be seen  If this condition is present, redeployment of the server will be required to create successful backups as use of WID and SQL on the same server is not supported by Microsoft itself.  This condition impacts all vendors who leverage VSS, including Microsoft's own DPM.  


Related KBs:
Windows Volume Shadow copy Services (VSS) Problem Determination:


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