COM Server Application Local Activation permissions

In some cases you will see the following error in the system event log:

The application-specific permission settings do not grant Local Activation permission for the COM Server application with CLSID {61738644-F196-11D0-9953-00C04FD919C1} to the user \mossService SID (S-1-5-21-). This security permission can be modified using the Component Services administrative tool.

To fix this you must grant location activation permissions to the service account user by doing the following:

1. Copy the CLSID in the error message
2. Open regedit, and search for the CLSID
3. Make a note of the service name, typically it will be the IIS WAMREG admin service
4. Open the Component Services MMC (under administrative tools)
5. Expand Component Services -> Computers -> My Computer -> DCOM Config
6. Find the application you noted earlier, right click on it and select properties
7. Under the Security tab, select 'customized' for Launch and Activation Permissions, and then select 'edit'
8. Add the service account and give it local activation and launch permissions, also give it remote permissions if needed.
9. Click OK.
10. Restart IIS

That should solve that error message.