Had a user who was getting blank screens when opening chat windows for Skype for Business and he couldn’t see text or type in messaging window so I thought I’d reset all the settings :

1)

Close Lync.exe

Close Outlook.exe

2)

Delete Folder : \%AppData%\Roaming\Microsoft\Office\16.0\Lync

Delete in Registry following key:

HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\Lync

3) Reopen Skype for Business