Microsoft recommends that you perform an IISRESET after starting the User Profile Synchronization Service when Central Administration is running on the same SharePoint Server as the UPSS. However, this can be problematic in a live production environment where you don’t want to interrupt the user experience. What really needs to happen is for the Central Administration Application Pool to be recycled. For those of you who don’t have the ability to use the IIS Manager on the servers, here’s the PowerShell equivalent:
$appPool = gwmi -Namespace "root\MicrosoftIISv2" -class "IIsApplicationPool" | where {$_.Name -eq "W3SVC/APPPOOLS/SharePoint Central Administration v4"} $appPool.Recycle()
Once you do this, you can manage the Synchronization Connections as well as initiate an Incremental/Full Sync. You’ll also notice that the Profile Synchronization Status is Idle and not “unprovisioned”.