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c#.netvisual-studiowin-universal-appvisual-studio-2015

Why do I keep getting "Safe handle has been closed" error for even a simple Hello World Universal Windows Platform Application in Visual Studio?

I keep getting the following error whenever I open the MainPage.xaml by the xaml editor. I actually get this error for almost all of my apps.

System.ObjectDisposedException
Safe handle has been closed
   at Microsoft.VisualStudio.DesignTools.HostUtility.Platform.AppContainerProcessDomainFactory.CreateDesignerProcess(String applicationPath, String clientPort, Uri hostUri, IDictionary environmentVariables, Int32& processId, Object& processData)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Primitives.ProcessDomainFactory.ProcessIsolationDomain..ctor(ProcessDomainFactory factory, IIsolationBoundary boundary, AppDomainSetup appDomainInfo, IIsolationTarget isolationTarget, String baseDirectory)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Primitives.ProcessDomainFactory.CreateIsolationDomain(IIsolationBoundary boundary)
   at Microsoft.VisualStudio.DesignTools.HostUtility.Platform.AppContainerProcessDomainFactory.CreateIsolationDomain(IIsolationBoundary boundary)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Primitives.IsolationBoundary.Initialize()
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Primitives.IsolationBoundary.CreateInstance[T](Type type)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.IsolatedObjectFactory.Initialize()
   at Microsoft.VisualStudio.DesignTools.DesignerHost.Services.VSIsolationService.CreateObjectFactory(IIsolationTarget isolationTarget, IObjectCatalog catalog)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.IsolationService.CreateLease(IIsolationTarget isolationTarget)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.IsolationService.CreateLease(IIsolationTarget isolationTarget)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.IsolatedDesignerService.CreateLease(IIsolationTarget isolationTarget, CancellationToken cancelToken, DesignerServiceEntry& entry, IServiceProvider serviceOverrides)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.IsolatedDesignerService.IsolatedDesignerView.CreateDesignerViewInfo(CancellationToken cancelToken)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.IsolatedTaskScheduler.InvokeWithCulture[T](CultureInfo culture, Func`2 func, CancellationToken cancelToken)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.IsolatedTaskScheduler.<>c__DisplayClass10_0`1.<StartTask>b__0()
   at System.Threading.Tasks.Task`1.InnerInvoke()
   at System.Threading.Tasks.Task.Execute()
Solution

  • I finally got it fixed by a weird method.

    I switched from developer mode to sideloading enabled mode and tried to reload the designer which failed saying I need a developer license to do so. I then reverted back to developer mode and again tried to reload the designer. This time it worked.

    Now I have to perform the above steps for every project which failed to load(including new projects) to load them successfully.

    Once the XAML designer loads successfully for a project, it will surely load successfully every time subsequently.