When you install the Lync Server 2013 Eval version it expires in 180 days & your Lync Server Front end service fails to start. To overcome this problem, we can convert the Lync Server Eval version to the Full version by following the steps below.

Before we see the conversion process its better we check what version we are running using the following methods.

Check Lync Sever version using the Lync Management Shell: Get-CsServerVersion

You will get either of the results: "Evaluation" or "Volume License Key installed" Check the Lync Server Version using the Registry Method (basically this is what the above PowerShell command does, it looks up for this registry & fetches us the result): Open Registry Editor & navigate to the following key:

HKEY_LOCAL_MACHINESOFTWAREMicrosoftReal-Time Communications{A593FD00-64F1-4288-A6F4-E699ED9DCA35}Type

You will either see "Volume License" or "Evaluation License" So how do we covert an Eval version Lync Server to Full version?

• We need to copy the "Server.msi" from the licensed copy of installation media & replace it with the "server.msi" in the eval media. (Rename the old server.msi in the eval to .old before copying it over).
• Next open Lync Management Shell & run the following command:
• C:> msiexec.exe /fvomus "c:server.msi" EVALTOFULL=1 /qb
• After the command completes successfully run the following command:
• Enable-CsComputer.
• Now runGet-CsServerVersionto check if the lync is converted to full licensed version.
• Finally we need to make sure all the service are running by using the command:
• Get-CsWindowsService You will see the below result: Status Name ActivityLevel -- -- ----- Running W3SVC Running MASTER Running REPLICA Running RTCCLSAGT Stopped RTCSRV Incoming Requests per Second=0,Messages in Server=0,Incoming Messages Held=0 Running RTCCAA Concurrent Calls=0 Running RTCCAS Concurrent Conferences=0 Running RTCRGS Current Active Calls=0
• You will notice that theRTCSRV (Lync Front End Service)will be stopped. We need to start by running start-CsWindowsService.