...
Sometimes the Skype for Business/Lync address book is not up to date. New users do not show up when searching. Those users are local and should show up immediately.
...
Resolution
Client versions
15.0 = Skype for Business 2015
16.0 = Skype for Business 2016
replace 16.0 below corresponding to the client version.
- Remove the GalContacts.db and GalContacts.db.idx files
- Go to "%localappdata%\Microsoft\Office\16.0\Lync\sip_<username>"
- Remove The GalContacts.db and GalContacts.db.idx files
- To speed up the process of downloading the GAL files add a registery key
reg add HKLM\Software\Policies\Microsoft\Office\16.0\Lync /v GalDownloadInitialDelay /t REG_DWORD /d 0 /f