Microsoft have released update rollup 1 for Windows Server 2012 Essentials.
The update adds four features and fixes seven issues, for details on the items addressed see the knowledge base article KB2781267.
On my test server, the update installed in less then 5 minutes directly from Windows Update.
Note 1: The update rollup contains the server-side fixes. After the update is applied to the server the client-side update KB2781268 will be applied to the client computers automatically. You do not need to download the client-side update, as it is downloaded automatically along with the server update rollup 1.
Note 2: If you have Office 365 Integration services running prior to installing update rollup 1 you will need to run the following PowerShell commands.
Set-Service -Name PwdSyncProviderSvc -StartupType Automatic
Set-Service -Name PwdSyncProviderSvc -Status Running
Set-Service -Name O365ProviderSvc -Status Running
See the Technet Article here for more details: