Issues when deleting a workflow manager farm

Hi,

I am facing an issue with one workflow manager farm.  I would like to remove the machine from the farm because I see there are some issues. The farm was installed with auto-generated certificates. There is only one host in this farm. It is a staging farm.

First running get-wffarm will give me this output:

Get-WFFarm : Certificate requested with thumbprint

64701BE5CE61E7A6A61DC4C27FEBDD5E4625B5F3 not found in the certificate store
LocalMachine\My.
At line:1 char:1
+ Get-WFFarm
+ ~~~~~~~~~~
+ CategoryInfo : NotSpecified: (:) [], InvalidOperationException
+ FullyQualifiedErrorId : System.InvalidOperationException

Trying any of the remove-wfhost or trying to leave the farm using the wizard will give me: 

Remove-WFHost : Certificate requested with thumbprint
64701BE5CE61E7A6A61DC4C27FEBDD5E4625B5F3 not found in the certificate store
LocalMachine\My.
At line:1 char:1
+ Remove-WFHost
+ ~~~~~~~~~~~~~
+ CategoryInfo : NotSpecified: (:) [Remove-WFHost], InvalidOperat
ionException
+ FullyQualifiedErrorId : System.InvalidOperationException,Microsoft.Workf
low.Deployment.Commands.RemoveWFHost

Trying to uninstall the Workflow manager will give me a message that this host is part of a farm and I should remove it from the farm first.

Also I get those two events in the application event viewer:

Application: Microsoft.Workflow.Deployment.ConfigWizard.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.InvalidOperationException
Stack:
at Microsoft.ServiceBus.Commands.Common.DBEncryptionHelper.FindCert(System.String)
at Microsoft.ServiceBus.Commands.Common.DBEncryptionHelper.DecryptStringUsingCertificate(System.String, System.String)
at Microsoft.ServiceBus.Commands.Common.DBEncryptionHelper.DecryptDbConnectionStringIfEncrypted(System.String, System.String, System.String)
at Microsoft.ServiceBus.Commands.Common.ServerInfo.FillServerInfo(Microsoft.ServiceBus.Commands.Common.ServerInfo, System.String)
at Microsoft.Workflow.Deployment.Commands.WFServerInfo.GetWFServerInfo()
at Microsoft.Workflow.Deployment.ConfigWizard.FarmCreationModel.InitializeFromDataSourceForLeave()
at Microsoft.Workflow.Deployment.ConfigWizard.WelcomePage.LeaveFarmButton_Click(System.Object, System.Windows.RoutedEventArgs)
at System.Windows.EventRoute.InvokeHandlersImpl(System.Object, System.Windows.RoutedEventArgs, Boolean)
at System.Windows.UIElement.RaiseEventImpl(System.Windows.DependencyObject, System.Windows.RoutedEventArgs)
at System.Windows.Controls.Button.OnClick()
at System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonUp(System.Windows.Input.MouseButtonEventArgs)
at System.Windows.RoutedEventArgs.InvokeHandler(System.Delegate, System.Object)
at System.Windows.EventRoute.InvokeHandlersImpl(System.Object, System.Windows.RoutedEventArgs, Boolean)
at System.Windows.UIElement.ReRaiseEventAs(System.Windows.DependencyObject, System.Windows.RoutedEventArgs, System.Windows.RoutedEvent)
at System.Windows.RoutedEventArgs.InvokeHandler(System.Delegate, System.Object)
at System.Windows.EventRoute.InvokeHandlersImpl(System.Object, System.Windows.RoutedEventArgs, Boolean)
at System.Windows.UIElement.RaiseEventImpl(System.Windows.DependencyObject, System.Windows.RoutedEventArgs)
at System.Windows.UIElement.RaiseTrustedEvent(System.Windows.RoutedEventArgs)
at System.Windows.Input.InputManager.ProcessStagingArea()
at System.Windows.Input.InputProviderSite.ReportInput(System.Windows.Input.InputReport)
at System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr, System.Windows.Input.InputMode, Int32, System.Windows.Input.RawMouseActions, Int32, Int32, Int32)
at System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr, MS.Internal.Interop.WindowMessage, IntPtr, IntPtr, Boolean ByRef)
at System.Windows.Interop.HwndSource.InputFilterMessage(IntPtr, Int32, IntPtr, IntPtr, Boolean ByRef)
at MS.Win32.HwndWrapper.WndProc(IntPtr, Int32, IntPtr, IntPtr, Boolean ByRef)
at MS.Win32.HwndSubclass.DispatcherCallbackOperation(System.Object)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(System.Delegate, System.Object, Int32)
at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(System.Object, System.Delegate, System.Object, Int32, System.Delegate)
at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(System.Windows.Threading.DispatcherPriority, System.TimeSpan, System.Delegate, System.Object, Int32)
at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr, Int32, IntPtr, IntPtr)
at MS.Win32.UnsafeNativeMethods.DispatchMessage(System.Windows.Interop.MSG ByRef)
at MS.Win32.UnsafeNativeMethods.DispatchMessage(System.Windows.Interop.MSG ByRef)
at System.Windows.Threading.Dispatcher.PushFrameImpl(System.Windows.Threading.DispatcherFrame)
at System.Windows.Application.RunInternal(System.Windows.Window)
at System.Windows.Application.Run()
at Microsoft.Workflow.Deployment.ConfigWizard.App.Main()

And second:

Faulting application name: Microsoft.Workflow.Deployment.ConfigWizard.exe, version: 1.0.20922.0, time stamp: 0x505e1b30
Faulting module name: KERNELBASE.dll, version: 6.1.7601.18409, time stamp: 0x5315a05a
Exception code: 0xe0434352
Fault offset: 0x000000000000940d
Faulting process id: 0x187c
Faulting application start time: 0x01d03b18d175b354
Faulting application path: C:\Program Files\Workflow Manager\1.0\Microsoft.Workflow.Deployment.ConfigWizard.exe
Faulting module path: C:\Windows\system32\KERNELBASE.dll
Report Id: 10ab792b-a70c-11e4-b719-0050569a196f

Any idea on how to get rid of this workflow manager farm?