Pointer is not valid - object reference not set to an instance of an object (4247045)

Pointer is not valid - object reference not set to an instance of an object

You receive an error when a backup is attempted in GPOADmin.
When trying to backup manually error states
The pointer is not valid.
System.ServiceModel.FaultException`1[System.ServiceModel.ExceptionDetail]:
Object reference not set to an instance of an object.
(Fault Detail is equal to An ExceptionDetail, likely created by IncludeExceptionDetailInFaults=true, whose value is: System.NullReferenceException: Object reference not set to an instance of an object.
at GPOADmin.Interops.GpmGmt.IGPMGPO2.GenerateReport(GPMReportType GPMReportType, Object& pvarGPMProgress, Object& pvarGPMCancel)
at Quest.Avalanche.ClassLibrary.LiveEnvironment.PolicyBase.GetHtmlSettingsReport(Boolean isCloaked)
at Quest.Avalanche.VersionControl.Workflow.VersionControlled.GetSettingsReport(ControlledObjectInstanceType reportType, Boolean gpoHtmlReport)
at Quest.Avalanche.Reporting.ReportManager.GetGpoHtmlSettingsReportByType(Guid controlledObjectId, ControlledObjectInstanceType type)
at Quest.Avalanche.Reporting.ReportManagerStream.GetGpoHtmlSettingsReportByType(Guid gpoVcId, ControlledObjectInstanceType type)
at SyncInvokeGetGpoHtmlSettingsReportByType(Object , Object[] , Object[] )
at System.ServiceModel.Dispatcher.SyncMethodInvoker.Invoke(Object instance, Object[] inputs, Object[]& outpu...).

This has occurred due to an 'invalid' setting within the SecEdit file.
This only affects 2016 servers with a specific workaround implemented, which involves removing the following key and sub-values:
"HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SecEdit\Reg Values\MACHINE/Software/Microsoft/Windows/CurrentVersion/Policies/System/DontDisplayLockedUserId"

Specifically, the issue was caused because a workaround was implemented, which removes certain options from the GPO Editor, due to a Microsoft KB causing console crashes:
(Workaround 3)
http://cloudexchangers.com/issue-with-accessing-security-options-in-group-management-console-in-windows-server-2016/

This change, as of the December 2020 update can be safely reverted, and the console no longer crashes.
You should be able to merge the registry key back in if you still have it.
If you no longer have the registry key export, you will need to re-install GPMC on the affected servers.