Unexpected error calling routine RegOpenKeyExW(-2147483646,SYSTEM\CurrentControlSet\Services\VSS\Diag,...). hr = 0x80070005, Access is denied.
You may experience this on a Windows Server 2008 R2.
According to the research, the issue may be caused by an invalid entry inside the following registry sub tree.
HKey_Local_Machine\Software\Microsoft\Windows NT\CurrentVersion\ProfileList
Open the registry editor with regedit. Expand and local to the subtree, check if there is an entry that has a ".bak" value appended.
If so, this may be cause the failure when trying to resolve the SID of the writer. Please backup the registry key first, and then delete that entry with the extra ".bak" Then you may reboot the problematic server to check if it the issue can be fixed. HF.