Hello all,

We have a handful of users that regularly schedule Lync meetings via the "New Lync Meeting" button in Outlook 2013.  Lync is running version 2013 as well and both programs are installed locally as 32 bit versions on Win 7 x64 boxes.  At random intervals, the "New Lync Meeting" button will disappear from the toolbar at the top of their Outlook Calendar window.  The add-in becomes disabled and the users have to go to File > Options > Add-Ins to check the box to re-enable it.  This is obviously a hindrance to their workflow.  We've tried replacing the Lync add-in DLL (UCAddin.dll) with a good copy, uninstalling/reinstalling Office and Lync, deleting and recreating the user profiles and even replacing their PCs.  No luck with any of those steps with any of the users, as the problem is only fixed temporarily in each case.  The users do have multiple calendars and shared Inboxes attached to their profiles since they are secretaries, so their Outlook data files are obviously huge.  Not sure if that is a factor but I imagine it would introduce the possibility for issues/corruption.

Has anyone seen this behavior before and discovered a fix?  There do not appear to be any Office updates delivered through Windows update which resolve this issue, as one of the PCs I'm testing various fixes for the issue on is patched as up to date as possible.  I have been trying a script to make sure the DWORD value of the LoadBehavior entry for that add-in always stays set to 0x00000003 (enabled), but we haven't been having much luck with that either.  I would rather not deploy another script (especially one that runs constantly and eats up processing power) to our environment if it can be avoided.

Thanks in advance for your help,

Alex