When a Lync 2010 user is called or IM'ed their toast notification in the bottom right of their PC doesn't show up. I have had it happen for two users now utilizing Lync 2010 on Windows 8. The only temporary fix I've found is recreating their whole profile. I cant seem to find any assistance on this rather less documented issue.

Has anyone else ran into this issue?

I guess the profile for Lync 2010 was interrupted.

Please try to repair the Lync 2010 when you encounter the problem again.

Update you Lync 2010 to the latest version.

I tried windows updates, repairs, and even re-installations from the Microsoft volume licensing site - nothing worked. I installed the 2013 client and now it is working. The back end server is still 2010 but I haven't noticed any issues using the newest 2013 Lync client.