Skype for Business (unlicensed product)

1. Log out of Skype for Business.

2. Delete any sign-in information.

3. Exit Skype for Business.

4. Open Run bar and type in %AppData%. navigate to\Local\Microsoft\Office\16.0\Lync\ for Skype for Business and Lync 2016, or \Local\Microsoft\Office\15.0\Lync\ for Lync 2013.

5. Delete sip_profileName folder. If you do not see this folder, check the \Local\Microsoft\Communicator directory.

6. Delete all files in Tracing folder. Do not delete the folder itself.

7. Clear DNS cache: in Command Prompt run ipconfig /flushdns command. (If you can)