Running the Prepare Forest step for a new Lync Server 2013 deployment throws the error: “Value cannot be null.”

Problem

You’re performing a greenfield deployment of Microsoft Lync Server 2013 and execute the Prepare Current Forest step:

… but it fails with the error:

Prepare ForestEnable-CSAdForest -Verbose -Confirm:$false -Report “C:Usersa-tlukAppDataLocalTempEnable-CSAdForest-[2014_10_15][11_12_50].html”Creating new log file “C:Usersa-tlukAppDataLocalTempEnable-CSAdForest-085d5b10-3f1a-4136-9af5-b128bdc6a4c9.xml”.Enable the Active Directory forest to host Lync Server 2013 deployments.Prepare Forest Active Directory settings execution failed on an unrecoverable error.Creating new log file “C:Usersa-tlukAppDataLocalTempEnable-CSAdForest-[2014_10_15][11_12_50].html”.WARNING: Enable-CSAdForest failed.WARNING: Detailed results can be found at “C:Usersa-tlukAppDataLocalTempEnable-CSAdForest-[2014_10_15][11_12_50].html”.Command execution failed: Value cannot be null.Parameter name: instanceToDelete

Opening the detailed log shows the following:

Exiting the failed step shows that the Prepare Current Forest step has not completed:

Solution

While most of the solutions through searches suggest to use PowerShell to run this step, you can actually get through this error by simply putting in the domain that you would like the universal groups created: