Assume that you click the Join online meeting link to join an online meeting on a Microsoft Lync for Mac 2011-based device. In this situation, the meeting webpage opens, however, the Lync for Mac 2011 client does not start. Therefore, you cannot join the meeting.
Note This issue occurs occasionally.
To resolve this issue, install the following cumulative update:
2844274 Description of the Microsoft Lync for Mac 2011 14.0.5 update
For more information about a similar issue, click the following article number to view the article in the Microsoft Knowledge Base:
2844260 Attendees can't join an online meeting and the organizer joins the meeting as an attendee on a Lync for Mac 2011-based device