Skype for Business 2016 for MAC
In the Finder menu, click Go, and click Go to Folder.
Delete the following files:
- /Users/<User>/Saved Application State/com.microsoft.SkypeForBusiness.savedState
Delete the following file:
- /Library/Internet Plug-Ins/MeetingJoinPlugin.plugin
In the Applications/Utilities folder, open Keychain Access.
In your logon keychains, delete Skype for Business.