Microsoft Lync : Unable to Login due to certificate error

Do you experience this error and not able to sort it out. Here's some information that I can share with you. 



Fix Subject : Microsoft Lync 2010 certificate error in login

1.Browse to this location 

Windows XP
C:\Documents and Settings\<User>\Application Data\Microsoft\Crypto\RSA\

Windows 7
C:\Users\<User>\AppData\Roaming\Microsoft\Crypto\RSA\

2. Delete the Subfolder in RSA which should be like 
Ex : S-1-5-21-1832567678-2753014051-3571567910-103042

3. Restart machine and try login again.