Running Lync Client v4.0.7577.4087
User called stating he was unable to log into Lync and was getting a message about the Clock on his PC being wrong. He verified his time was correct but continued to get the error.
I looked at the machine, he lived 1 timezone behind that of the Lync servers and his TZ was set correctly. His time and date was correct based on his location. However the "Automatically Adjust for Daylight Savings" was not checked.
Somehow I got the feeling to check that box, which then skewed his time up +1 hours. I then re-adjusted his time to the correct time for his timezone and he was able to log in.
I'm not sure why this happened. Because VISUALLY his time was correct for his selected TZ originally.