Crumbs, the online/busy status of my Lync client isn't the same as my Outlook calendar

I don't hear this much, but I do hear it from customers.

There is a trend, nowadays, to have a hybrid setup in a customers Lync setup.  So they will have an on-premise Lync server and then expand into the LYO world, whilst keeping the Lync server operational (I'd thought I'd provide a video from our Lync conference in Las Vega describing this :) -

This is happening for loads of organisations now. It did happen for huge customers with loads of cash, but as the cloud gets cheaper we are seeing "ordinary customers" doing this.

Which isn't that bad.  What I did see, however, was a lot more issues with displaying free/busy information on the Lync client when used with Outlook / Exchange account.  The key issue here was that the SIP address was different from the SMTP address.  Not good when using the PC Lync add in for Outlook.  The SIP address is used by the plugin to see what meetings that user has, and if they are in one, will update the status of Lync.

Sometimes that won't happen. So if I have a user called as an SMTP address but the SIP address is  The presence information in the Lync client won't update from the Outlook client meetings.  Trouble there then! 

Easy to fix however!!! Change the SMTP address to equal the SIP address.....

Err ok, if you want something different then, just change the registry to tell Outlook not to be too harsh when looking to match the SIP and the SMTP address.  This registry change should help out:

  1. Click Start, click Run, type regedit, and then press ENTER.
  2. Locate, and then right-click the following registry subkey:
    1. HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Communicator
    2. HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Lync
  3. Point to New, and then click DWORD Value.  
  4. Type DisableEmailComparisonCheck as the name of new registry entry, and then press ENTER.  
  5. Double-click DisableEmailComparisonCheck, type 1 in the Value data box, and then click OK.  
  6. Close Registry Editor.
  7. Restart Lync and Outlook.   

So that should fix the issue, but you can also try re-registering the SMTP address with O365:

  1. In Office 365 admin portal, change the domain name of the user account from a custom domain such as to the default domain
  2. Wait for half an hour, check the SMTP address and SIP address using Windows Powershell.
  3. If the SMTP address and SIP address are shown as, change the domain for this user back to
  4. Check the results

 Please use a demo account, and don't hold me liable! This is your doing :)