Troubleshooting MS SharePoint backups

MS SharePoint backups depend on 3 VSS writers:

  1. SqlServerWriter
  2. SharePoint Services Writer (in MS SharePoint 2013, it is disabled by default and needs to be registered)
  3. OSearch VSS Writer

You can check the availability of these writers through a system console, for example the Command Prompt:

vssadmin list writers

When there is difficulty starting or completing a SharePoint backup, it often helps to troubleshoot the writers.

What to do if a writer is unavailable

If one of the writers is unavailable (missing from the response to vssadmin list writers), you can try some typical solutions before contacting support.

Name of missing writer Possible solutions
SqlServerWriter
  1. Make sure the SQL databases for SharePoint are located on the current server (multi-tier configuration is not supported).
  2. Make sure the names of the SQL databases on the current server do not contain spaces (see the Identifying spaces in the names of SQL databases section below).
  3. Check the status of the SQL Server VSS Writer service that handles the writer.
  4. Make sure the Writer has sufficient access permissions (see the Granting SQL Server VSS Writer access to the database section below).
SharePoint Services Writer
  1. Check the statuses of the services responsible for the writer: Volume Shadow Copy and SharePoint VSS Writer.
  2. (If the services are unavailable). Register the writer in the Windows registry.
  3. If MS SharePoint is installed on Windows SBS 2011 Standard, make sure the SharePoint Services Writer has sufficient access permissions (learn more).
OSearch VSS Writer Activate the SharePoint Server Search 14 service that handles the writer.

Checking the statuses of VSS writers

The VSS writers are activated through appropriate services. If any of the writers are not available, please start the Services Console and make sure the following services are available and their statuses are as follows:

  1. Volume Shadow Copy – must not be disabled
  2. SharePoint Server Search 14 – must not be disabled
  3. SQL Server VSS Writer – Started and set to the Automatic startup type
  4. SharePoint VSS Writer – Started and set to the Automatic startup type

Registering the SharePoint Services Writer

In MS SharePoint 2010 and 2013, you may need to register the SharePoint Services Writer in the Windows registry.

Sometimes the writer can be enabled but not participating in backups. In that case, it needs to be disabled and then enabled again.

Here are steps to follow:

  1. Start the Command Prompt. Go to the BIN directory.
    • MS SharePoint 2010: cd "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\BIN"
    • MS SharePoint 2013: cd "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\15\BIN"
  2. From the BIN directory, run the appropriate command:
    • stsadm -o unregisterwsswriter – to disable (unregister) the writer – learn more
    • stsadm -o registerwsswriter – to enable (register) the writer – learn more

Identifying spaces in the names of SQL databases

The names of SQL databases for MS SharePoint must not start or end with a space (this is crucial for successful backups). You can check it in the following way:

  1. In SQL Server Management Studio, right-click on any database. Select Run query.
  2. From sys.databases, run the following query:
select '#' + name +'#'

If detected, the spaces must be removed.

Granting SQL Server VSS Writer access to the database

Sometimes the access permissions granted to the SQL Server VSS Writer may be insufficient. This can happen in the following cases:

  • The Writer is running under a user with insufficient privileges.
  • The Writer does not have sufficient privileges to access the database.

Here is how to resolve the issue:

  1. Add permissions for the NT AUTHORITY/SYSTEM service logon and any user which you have mentioned as service logon.
  2. Check SQL server security attributes for the user selected as service logon for SQL writer and add sysadmin privileges.