Preparing Active Directory is one of the most important part of Installing Skype for Business 2015. I prepared Schema without any issue but when I started "Prepare Current Forest", it failed with the following error.

  • Error: Object reference not set to an instance of an object.
  • Error: Value cannot be null. Parameter name: instanceToDelete
  • Error: An error occurred: "System.ArgumentNullException" "Value cannot be null. Parameter name: instanceToDelete"

Enable-CsAdForest Failed

Solution

The simple solution is to prepare current forest for SFB 2015 using Skype for Business Server Management Shell.

Command Syntax

Enable-CsAdForest -GroupDomain DomainName -GlobalSettingsDomainController DCName -GroupDomainController DCName -GlobalCatalog DCName

Example

Enable-CsAdForest -GroupDomain Test.com -GlobalSettingsDomainController DC1.Test.com -GroupDomainController DC1.Test.com -GlobalCatalog DC1.Test.com

Note: You must have at least Enterprise Admin rights in Active Directory to prepare current forest either via GUI or PowerShell.