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.
Resolution
To fix this issue, install the January 2018 cumulative update 6.0.9319.514 for Skype for Business Server 2015, core components.
