Veeam Backup for Office 365 – Invalid Exchange Server version

Since few days, Veeam’s support received this error from some end-users about Veeam Backup for Office 365 (release “Invalid Exchange Server version” during backing up of mailboxes (Veeam Backup for Office 365 – Invalid Exchange Server version). The issue is confirmed, the quick fix is in place…

Warning message: “Processing mailbox xxx failed with error: Invalid Exchange Server version“.

Some more info from logs (source: Veeam Forum):

8/25/2017 1:46:08 AM 13 (6196) Adding 1 mailboxes in processing…
8/25/2017 1:46:08 AM 13 (6196) Processing mailbox: xxx…
8/25/2017 1:46:08 AM 13 (6196) Connecting to Exchange Web Services…
8/25/2017 1:46:08 AM 13 (6196) Host:
8/25/2017 1:46:08 AM 13 (6196) Requesting folder hierarchy changes…
8/25/2017 1:46:09 AM 13 (6196) No folder hierarchy changes
8/25/2017 1:46:09 AM 13 (6196) Preparing folders for items processing…
8/25/2017 1:46:09 AM 13 (6196) Error: Invalid Exchange Server version
8/25/2017 1:46:09 AM 13 (6196) Stack:
8/25/2017 1:46:09 AM 13 (6196) at Veeam.Ews.ExServices.GetExchangeServerVersion()
at Veeam.Ews.ExServices.get_ExchangeServerVersion()
at Veeam.Archiver.Source.MailboxActivator.PrepareFolders(IMailboxContext bind, ExFolder top, ExcludedFolders excluded, CancellationToken cancel)
at Veeam.Archiver.Source.MailboxActivator.DoMailboxWork(CancellationToken cancel)
at Veeam.Archiver.Source.MailboxAction.DoWork(CancellationToken cancel)
8/25/2017 1:46:09 AM 13 (6196) Mailbox processing failed: xxx

It looks like the version of back-end Exchange servers in Microsoft Office 365 has been quietly changed by Microsoft. The development team is aware of this issue and had been working towards the resolution.

Solution – Apply this patch :

  • First, stop all the jobs,
  • Stop “Veeam Backup for Microsoft Office 365 Service”,
  • Then, you can replace the original file: “Veeam.Ews.dll” file, located in “C:\Program Files\Veeam\Backup365” folder by this one: FIX 113114. You have to keep the same file name.
  • Note: Keep the source file as “Veeam.Ews_OLD.dll“,
  • Start “Veeam Backup for Microsoft Office 365 Service”,
  • Retry the job.

You can learn more about Veeam Backup for Office 365 v1.5 and v2 new features here.

Veeam Availability Suite 9.5 first full availability solution! Full description!

You can learn more about Veeam Backup & Replication 9.5 here.

You can learn more about Veeam Availability Suite 10 and VeeamON 2017 announcements here.

Veeam Agent for Windows step by step installation guide.

If you need to disable UAC Server on Windows Server 2016 Script Guide.


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