Windows Server 2016 Essentials client backup fails with OutOfMemoryException

Question

Client backup fails for one (large) disk. (Backup of this disk worked fine until recently.) Event log on the client shows a ServerEssentials\Admin log error:

Backup job 5 on <server> did not succeed.
Reason: ClientException, OutOfMemoryException; Array dimensions exceeded supported range.; at System.Collections.Hashtable.rehash(Int32 newsize, Boolean forceNewHashCode)
at System.Collections.Hashtable.Insert(Object key, Object nvalue, Boolean add)
at Microsoft.WindowsServerSolutions.DataProtection.PCBackup.BackupOp.BackupOperation.ProcessFileRecord(Int64 index, FileRecord fr)
at Microsoft.WindowsServerSolutions.DataProtection.PCBackup.BackupOp.BackupOperation.DoFileRecordPass()
at Microsoft.WindowsServerSolutions.DataProtection.PCBackup.BackupOp.BackupOperation.RunWithoutCatch()
at Microsoft.WindowsServerSolutions.DataProtection.PCBackup.BackupOp.BackupOperation.Run()
at Microsoft.WindowsServerSolutions.DataProtection.PCBackup.BackupOp.BackupSetOperation.RunWithoutCatch()
at Microsoft.WindowsServerSolutions.DataProtection.PCBackup.BackupOp.BackupSetOperation.Run()

On the server, I've tried to "Customize backup for the computer" for this client (with "Add or remove backup items"), but this hangs when I try to expand the folder list for the problem disk. (On the client, the "Windows Server Essentials Client Service Host" stops running at this point.)

How can I fix or work around this to get a successful backup?

Answer 1

Hi,

I resolved a similar issue by deleting C:\Users\<username>\AppData\Local\Microsoft\PCBackup

I hope this answers your question.

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Answer 2

I found the problem. When I ran WinDirStat on the disk that was failing backup, WinDirStat failed with "This application has requested the Runtime to terminate it in an unusual way". As an alternative to WinDirStat, I installed and ran WizTree. Ultimately I found that in %APPDATA%\com.adobe.dunamis\aad48341-26c0-47e0-b842-ed371541ac18\v1, some Adobe software had created an enormous number of empty directories. When I deleted all these (via command line "rmdir /S"), backup of the disk began succeeding again.

A Google search of "com.adobe.dunamis" shows that this problem (i.e., huge number of empty directories created in Adobe com.adobe.dunamis subfolder) has been reported multiple times on the Adobe Support Community forum since at least September 2021, wreaking various kinds of system havoc and wasting many hours of users' time. Once my backups were working again, I followed up by cancelling my Adobe Creative Cloud subscription and removing all Adobe software and files.