VSS IVssWriterCallback Error Occurs When Creating Backup

Problem:

Event Log ID 8194 is logged when a backup is run. A sample error is shown below:

Volume Shadow Copy Service error: Unexpected error querying for the IVssWriterCallback interface. hr = 0x80070005. This is often caused by incorrect security settings in either the writer or requestor process.

Operation:
   Gathering Writer Data

Context:
   Writer Class Id: {57af97e4-4a76-4ace-a756-d11e8f0294c7}
   Writer Name: SPSearch VSS Writer
   Writer Instance ID: {e959c0c6-8ce8-4f80-9f2d-9e4deb1d4596}

Note that error details may vary.

Cause:

Note: If this error is logged along with Event ID 12293, please see KB article Error: VSS Snapshot Creation Failed.

Note: If this error is logged along with Event ID 4001, please see KB article Backup Fails with VSS Event 4001.

This error is caused by incorrect or missing COM access permissions and does not affect the use of Image for Windows.

Solution:

To set the correct permissions and prevent the error from occurring, follow the instructions below:

1. Press and hold the Windows key and press R to pull up the Run dialog. Alternatively, if Run... is available from the Start Menu you can access it from there.
   
   
2. Type dcomcnfg into the box and click OK. The Component Services window will appear.
   
   
3. In the left portion of the window, expand the Component Services section and then expand the Computers section.
   
   
4. Right-click on My Computer (listed in the Computers section) and select Properties from the pop-up menu.
   
   
5. Click the COM Security tab. The My Computer Properties dialog will appear.
   
   
6. Click the Edit Default... button in the Access Permissions section. The Access Permission dialog will appear.
   
   
7. Under the Group or user names box, click the Add... button.
   
   
8. Type Network Service into the box and click OK.
   
   
9. Click OK on both the Access Permission and My Computer Properties dialogs to close them.
   
   
10. Restart Windows.