NullReferenceException occurs when you remove Skype for Business Server 2015

Applies to: Skype for Business Server 2015

Symptoms


Assume that you try to remove Microsoft Skype for Business Server 2015 or run the bootstrapper.exe /scorch command in a Skype for Business Server 2015 environment. Then a NullReferenceException occurs and the uninstallation fails together with the following call stack:

at Microsoft.Rtc.Management.Deployment.Roles.WebServices.ConfigIISAppWindowsAuth() server.vdomain.com(server.vdomain.com): at Microsoft.Rtc.Management.Deployment.Roles.WebServices.LocalDeactivate(IService service, Fqdn fqdn, Boolean complete) server.vdomain.com(server.vdomain.com): at Microsoft.Rtc.Management.Internal.Utilities.LogWriter.InvokeAndLog[T1,T2,T3](Action`3 action, T1 arg1, T2 arg2, T3 arg3) server.vdomain.com(server.vdomain.com): at Microsoft.Rtc.Management.Common.Reporting.LogWriterImpl.InvokeAndLog[T1,T2,T3](Action`3 action, T1 arg1, T2 arg2, T3 arg3) server.vdomain.com(server.vdomain.com): at Microsoft.Rtc.Management.Deployment.Tasks.HostLocalDeactivateTask.Action() server.vdomain.com(server.vdomain.com): at Microsoft.Rtc.Management.Internal.Utilities.LogWriter.InvokeAndLog(Action action) server.vdomain.com(server.vdomain.com): at Microsoft.Rtc.Management.Common.Reporting.LogWriterImpl.InvokeAndLog(Action action) server.vdomain.com(server.vdomain.com): at Microsoft.Rtc.Management.Deployment.DeactivateMachineCmdlet.InternalProcessRecord() server.vdomain.com(server.vdomain.com): at Microsoft.Rtc.Management.Deployment.DeploymentCmdlet.CmdletProcessRecord() server.vdomain.com(server.vdomain.com): --- End of inner exception stack trace --- server.vdomain.com(server.vdomain.com): at System.Management.Automation.Runspaces.PipelineBase.Invoke(IEnumerable input) server.vdomain.com(server.vdomain.com): at Microsoft.Rtc.Internal.Tools.Deploy.Tools.PowerShellRunner.RunCmd(String script, Collection`1& errors) server.vdomain.com(server.vdomain.com): at Microsoft.Rtc.Internal.Tools.Deploy.Tools.PowerShellRunner.RunCmd(String script) server.vdomain.com(server.vdomain.com): at Microsoft.Rtc.Internal.Tools.Deploy.Tools.InPlaceDeploymentSteps.PrepareForUpgrade(Object param) server.vdomain.com(server.vdomain.com): at Microsoft.Rtc.Internal.Tools.Deploy.ViewModels.DeploymentStepViewModel.Action(Object param) server.vdomain.com(server.vdomain.com): at Microsoft.Rtc.Internal.Tools.Deploy.Commands.RunDeploymentCommand.RunSteps(Object obj) SkypeServerUpdateInstaller.exe Error: 0 : server.vdomain.com(server.vdomain.com): System.Exception: Installation failed with code 10

Note This issue occurs after you apply December 2017 cumulative update 6.0.9319.510.