That’s a much more user-friendly fix (which worked for me) – and it’s one to add to the project FAQ list. Hope that helps and is typically easier than deleting entries. We provide this as post-migration steps to users once we move their mailboxes to 365. We’ve resolved this by having users sign out of Lync and then choose “Delete my sign-in info”, then just sign back in and their Lync client now connects to 365.

One suggestion given to me to force a new autodiscovery search was to wipe the user’s cached client information (in That sounded a little destructive but Richard’s post suggests removing a single registry better though is the solution from a comment on Richard’s blog post, from “Chad”:

If we looked at the configuration information for the Lync client (by Ctrl+right clicking on the Lync taskbar icon), we could see that the client was not autodiscovering the move to Exchange Online and still showed on-premises Exchange details, instead of a blank EWS Internal URL and an entry of for the EWS External URL. KB3007876 October 2014 Update für Lync für Mac 2011 14.0. Conferences You can have a meeting without leaving your computer by using the Lync phone (PC to PC with the use of headphones or speakers and a microphone), video, or IM conferences using Microsoft Lync. The reason for this is unclear but I’m not the only one who’s experienced it – Richard Brynteson describes exactly the same scenario where, after a migration from an on-premises Exchange mailbox to Exchange Online, the Lync 2013 client is unable to connect to the Exchange server and pull conversation history and meeting information. All your conversations are archived by date and contact. For Mac users, the conversation history is not saved to the Exchange account, but instead is saved locally to the Mac. In addition to the challenges created by the unified contacts store, my recent Office 365 migration project saw some issues where a user’s Lync/Skype for Business client failed to pick up a change in Exchange Web Services (EWS) as part of the move to Skype for Business Online. Optionally, also remove Microsoft Lync History.

Lync for mac 2011 conversation history