Skype for Business: Fix “Cannot sign in because the server version is incompatible with Microsoft Lync” Error.

If you installed Microsoft Office, your Lync client will be upgraded to the newer version. If you are in an olderOffice Communication Server (OCS) environment, this can cause an incompatibility issue. You’ll get an error when you attempt to sign in that says:

“Cannot sign in because the server version is incompatible with Microsoft Lync. Contact your support team with this information.”

Fortunately, there is a registry hack that will get you working again.

1. Select “Start“, type “regedit“, then press “Enter“.
2. Navigate to the following path:
   • HKEY_LOCAL_MACHINE / SOFTWARE / Policies / Microsoft / Office / 16.0 / Lync
     Note: If you have an older version of Skype for Business or Lync, 16.0 should be listed as 15.0.
3. Create a new DWORD 32-bit value called “DisableServerCheck” and set the “Data” to “1“.

Now close out of the Registry Editor and give it a try. Skype For Business should work just fine now with OCS.