Data Backup and Recovery

Microsoft Exchange 2016 CU5 - Breaks SMBR


Cumulative Update 5 (CU5) for Microsoft Exchange Server 2016 was released on March 21, 2017.



  • The Cumulative Update 5 package can be used to run a new installation of Exchange Server 2016 or to upgrade an existing Exchange Server 2016 installation to Cumulative Update 5.
  • It’s not necessary to install any Exchange Server 2016 cumulative updates or service packs that were released before Cumulative Update 5 before you install this update.

Upgrading and running Microsoft Exchange 2016 w/ Cumulative Update 5 (CU5)  discontinues the functionality of individual mailbox or mail item restores. This change in the Exchange platform is known to effect multiple backup products including Kroll OnTrack (Also white labelled as NetApp’s Single Mailbox Recovery (SMBR)single, Veritas Backup Exec, and Veeam Backup & Replication.


There is currently no path to roll back to CU4 from CU5, and no ETA on a resolution. It is possible that Microsoft may re-release CU5 or offer a fix within CU6.

In the absence of a fix or workaround, it is recommended to ensure proper quotas are defined within Exchange with regards to Deleted Items Retention. It should also be a reminder to confirm healthy and successful backups are in place.



Here are the vendor released KB articles:

Kroll Ontrack PowerControls for Exchange cannot open database on Exchange 2016 CU5


Veritas Backup Exec – Exchange 2016 CU5 Support


After installing CU5 for Exchange 2016, Backup Exec 16 will not show GRT items during restore


Published in the recent Veeam Digest

“You may want to hold off upgrading to the recently released Cumulative Update 5 (KB4012106) if mailbox item-level recovery is important for you. A couple of customers who already upgraded reported us restore failures in Veeam Explorer for Exchange, and after researching those we have found the cause being the significant change in one mailbox database structure. We’re now updating Veeam Explorer for Exchange to be able to parse the new blob format correctly, and are planning to include the fix in Veeam Backup & Replication 9.5 Update 2 – which we’ll be delaying for about a week over this and a few other last minute issues.”



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You're welcome.


Has anyone else had any information regarding this - or an update for SMBR (now that Exchange 2016 CU6 has been released) ??


Any news on this issue?!

Veeam fixed it within a week, Veritas in 3 months, but Netapp still is busy?!


A pre-release version of SMBR is available to address issues resulting from Exchange 2016 updates. NetApp support can provide a download.  There's a new install and a patch that adds CU6 support!




This pre-release has bugs and cant read all (sub)items from EDB file. Some mailboxes cant be opened at all. Hopefull this bugs wil be resolved soon!


@FREDGARCIA1 By the time you posted yesterday, the pre-release was already the official release.


SMBR 7.2.1 should be compatible through Exchange 2016 CU5.  Exchange 2016 CU6 included changes that caused issues similar to what you're describing.


I suggest opening a ticket to get the patch for CU6 to see if that resolves the situation. 


I am getting issues with CU5 and SMBR 7.2.1 SMBR mounts the source databse file but has a function call failure when you try to do anything with an account. I have checked the DB files in stellar phoenix mailbox exchange recovery and can see all the folders and mails so the file looks fine is just SMBR cannot read it.


Stellar Phoenix Exchange Recovery is a different type of product. The results their are not indicitive of the health of a database, but what it can do in a recovery situation.  That may be a good solution for you, but I suggest opening a ticket for support of the SMBR error to find out what the cause may be. 


Netapp have provided us with an update .dll for SMBR which has fixed the issue so for anyone else that come accross this log a call with tech support.



new in this release:

Single Mailbox Recovery 7.2.1 supports Microsoft Exchange Server 2016 Cumulative Update 5.