I recently had to enable all users in a specific OU for Skype for Business 2015. Easily done with Powershell; Either import the skypeforbusiness module into a normal Powershell window or run the Skype for Business Server Management Shell import-module skypeforbusiness Get-CsAduser -OU “OU=ExampleOU,DC=example,DC=com” | Enable CSuser -RegistrarPool “your pool name” -SipAddressType emailaddress