Issues

Although the Lync 2013 / Skype for Business 2015 installation seems simple, there are a few caveats in some scenarios

If your forest is made of several domains:

• You cannot run the initial schema update from a machine which is in any child domain.  The following steps must be run in the root domain :
  • Install-CsAdServerSchema
  • Enable-CsAdForest but you can target a child domain.
• The only action you must perform in the child domain is:
  • Enable-CsAdDomain
• Imagine you have an Active Directory is made of a top empty domain and a child where every real user resides.
  When you prepare the universal groups and want to have them in the child domain, you cannot use the setup graphical interface. The setup wizard makes you believe you can specify a domain which is not the root domain.
  
  But in all cases I saw, this fails with an error message saying "Error: Object reference not set to an instance of an object. Type: NullReferenceException at Microsoft.Rtc.Management.Deployment.LcForest.PrepareForest()".

  1	But in all cases I saw, this fails with an error message saying "Error: Object reference not set to an instance of an object. Type: NullReferenceException at Microsoft.Rtc.Management.Deployment.LcForest.PrepareForest()".

  
  You can however bypass this problem by using the Lync shell.
  Use the Enable-CsAdForest with the GroupDomain and GroupDomainController switches to manually specify the domain and the target Global Catalog to use.
  In child.forest.dom this would mean:
  
  Enable-CsAdForest example

  PowerShell

  Enable-CsAdForest -GroupDomain child.forest.dom -GroupDomainController DC-in-child.child.forest-domain -verbose -report myreport.html

  1	Enable-CsAdForest -GroupDomain child.forest.dom -GroupDomainController DC-in-child.child.forest-domain -verbose -report myreport.html

  
   

Complete Skype for Business installation sequence

A complete Active Directory preparation sequence would then be:

You can of course name your report html pages differently. You can include date, time or machine name. You canalso  test the final result with Get-CsAdDomain.

It is also worthwhile to note that you may end up with problems if your AD groups start with ‘CS’ as these letters are used for the Skype for Business built-in groups.