Restoring core services in Lync is one thing, but the users will certainly complain if they discover that all of their saved contacts or conference information is lost. It is not critical to restore the user database, but it's highly recommended to have a backup of the user data. This is not only intended for disaster recovery but also to help single users if their information is corrupted.
PowerShell is the only tool available to perform this task, running in the elevated prompt. The commands listed here will fail unless we provide information about where the user databases are stored. Before running any of these commands, run Get-CsService –UserDatabase and take note of the listed database(s), as shown in the following screenshot:
