Unified Contact Store requires Lync user to be migrated to Office 365 before Exchange mailbox

This content is 9 years old. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time. Please be warned that the information here may be out of date.

In a recent Office 365 project, I came across an issue where, if we migrated a user’s Exchange 2013 mailbox to Exchange Online before we migrated their Lync 2013 user to Skype for Business Online, the Move-CsUser cmdlet generated an error:

Move-CsUser: Exception of type ‘Microsoft.Rtc.Management.AD.Helpers.RollbackException’ was thrown

This is described in Camille de Bay’s blog post and appears to be related to the Unified Contact Store, which is enabled by default with Lync 2013 and Exchange 2013. There appear to be two options:

Migrate Lync before Exchange
Use the -force switch with the Move-CsUser cmdlet (which will result in a loss of contacts)

Dave Stork goes on to describe some issues with a combination of the UCS, Lync on-premises and Exchange Online (and these appeared to apply to my Lync 2013/Skype for Business Online hybrid solution too).

Microsoft knowledge base article 2614614 has lots more information on integrating Exchange Online with Skype for Business Online, Lync Server 2013, or a Lync Server 2013 hybrid deployment