Microsoft released two Lync-Related KBs today:
On-premises Lync Server integration with Exchange Online fails (KB2907651) deals with Exchange Online integration with an on=premises Lync Server 2010 or 2013. The issues described are Lync client Autodiscover process failure and EWS integration failure (EWS Information item is displayed as Not Deployed).
The fix for the above issues is to add the following registry key:
For Lync 2010 clients: Under HKEY_CURRENT_USER\Software\Microsoft\Communicator\, add a DWORD key named “OverrideDirectHttpConnection” with the value “1”.
For Lync 2013 clients: Under HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Lync\, add a DWORD key named “OverrideDirectHttpConnection” with the value “1”.
if you Lync Server 2013 Front-End server services don’t start for a long time (Who didn’t experience this?!), this article (KB2918336) can help.
This can happen after you install updates that require a service or system restart or if the Lync Server pool hosts three or more Lync Server 2013 Front-End servers.
If you see LS User Services Event ID: 32174, you might want to look into this article that suggests you run the command Reset-CsPoolRegistrarState -PoolFqdn “<Servers’ FQDN>” -ResetType QuorumLossRecovery.