Network Backup Causes VSS Error 8194

After setting up a new Windows 10 desktop in an Essentials 2012R2 domain, every day when the Essentials backup runs, backing up the machine across the network, I see this error:

Log Name:      Application
Source:        VSS
Event ID:      8194
Level:         Error
Description:
Volume Shadow Copy Service error: Unexpected error querying for the IVssWriterCallback interface.  hr = 0x80070005, Access is denied.
This is often caused by incorrect security settings in either the writer or requestor process.
Operation:
Gathering Writer Data
Context:
Writer Class Id: {e8132975-6f93-4464-a53e-1050253ae220}
Writer Name: System Writer
Writer Instance ID: {a086d867-ea91-464c-a295-a91100e8248b}

There are several references online to this error, for example:

http://help.remote-backup.com/index.php?/Knowledgebase/Article/View/327/5/eliminating-vss-error-8194-from-event-log
https://www.terabyteunlimited.com/kb/article.php?id=563

All of them that I found recommend changing the default DCOM permissions. I would rather change permissions for a specific DCOM component than for all components. I tried granting NETWORK SERVICE Lunch and Activation permissions on the Volume Shadow Copy Service component, App ID {56BE716B-2F76-4dfa-8702-67AE10044F0B} following the instructions in this blog post.

Unfortunately, that wasn’t enough; I still got the VSS 8194 errors. So I’m going with the change to default permissions as recommended by the above articles. Start dcomcnfg.exe, right-click on My Computer, select Properties, then grant NETWORK SERVICE Local Access to all COM components as shown:

VSS-error-8194-3

That change did finally stop the VSS 8194 errors.

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