Hi,
According to my knowledge, I would suggest you try the method in the following article to see if it helps.
From elevated cmd (run as Admin) execute following commands sequentially …
Takeown /f %windir%\winsxs\temp\PendingRenames /a
icacls %windir%\winsxs\temp\PendingRenames /grant "NT AUTHORITY\SYSTEM:(RX)"
icacls %windir%\winsxs\temp\PendingRenames /grant "YourDomain\Domain Admins":(RX)
icacls %windir%\winsxs\temp\PendingRenames /grant "YourDomain\Domain Users":(RX)
icacls %windir%\winsxs\temp\PendingRenames /grant "NT Service\trustedinstaller:(F)"
icacls %windir%\winsxs\temp\PendingRenames /grant BUILTIN\Users:(RX)
Takeown /f %windir%\winsxs\filemaps* /a
icacls %windir%\winsxs\filemaps*.* /grant "NT AUTHORITY\SYSTEM:(RX)"
icacls %windir%\winsxs\filemaps*.* /grant "NT Service\trustedinstaller:(F)"
icacls %windir%\winsxs\filemaps*.* /grant BUILTIN\Users:(RX)
net stop cryptsvc && net start cryptsvc
net stop vss && net start vss
net stop Winmgmt && net start Winmgmt
P.S. Replace the name of your domain in place of YourDomain !
Make sure to Reboot the Server after running the above commands. Run vssadmin list writers from elevated cmd and you should see the missing or problematic Writer Listed without any errors.
https://social.technet.microsoft.com/wiki/contents/articles/7309.backup-fails-with-error-message-writer-missing-or-failed-or-timed-out-or-waiting-for-completion-in-vssadmin.aspx
Best Regards,