NuGet VS extension version: 3.2.60914.10516

1. In Visual Studio 2015, File -> Open -> Open File
2. Open a project.json file that belongs to a project (in my example, a desktop-targeted class library project)
3. Put the caret on the version string of a Nuget package dependency expressed in that project.json file.
4. Press Ctrl+J (to activate the intellisense completion dropdown)

The ArgumentNullException is thrown from Path.Combine when it is called from here.

    ---------------------------
    Microsoft Visual Studio
    ---------------------------
    An exception has been encountered. This may be caused by an extension.
    You can get more information by examining the file 'C:\Users\andarno\AppData\Roaming\Microsoft\VisualStudio\14.0exp\ActivityLog.xml'.
    ---------------------------
    OK   
    ---------------------------

The activity log contained this exception:

Microsoft.VisualStudio.Composition.CompositionFailedException: An exception was thrown while initializing part "NuGet.PackageManagement.VisualStudio.VSSettings". ---> System.ArgumentNullException: Value cannot be null. Parameter name: path1 at System.IO.Path.Combine(String path1, String path2) at NuGet.PackageManagement.VisualStudio.VSSettings.ResetSolutionSettings() at NuGet.PackageManagement.VisualStudio.VSSettings..ctor(ISolutionManager solutionManager, IMachineWideSettings machineWideSettings) --- End of inner exception stack trace --- at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.RuntimePartLifecycleTracker.CreateValue() at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.Create() at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.MoveNext(PartLifecycleState nextState) at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.MoveToState(PartLifecycleState requiredState) at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.GetValueReadyToExpose() at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.<>c__DisplayClass15_0.b__0() at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.GetValueForImportElement(RuntimePartLifecycleTracker importingPartTracker, RuntimeImport import, RuntimeExport export, Func3 lazyFactory) at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.GetValueForImportSite(RuntimePartLifecycleTracker importingPartTracker, RuntimeImport import) at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.RuntimePartLifecycleTracker.<CreateValue>b__10_0(RuntimeImport import) at System.Linq.Enumerable.WhereSelectEnumerableIterator2.MoveNext() at System.Linq.Buffer1..ctor(IEnumerable1 source) at System.Linq.Enumerable.ToArray[TSource](IEnumerable1 source) at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.RuntimePartLifecycleTracker.CreateValue() at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.Create() at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.MoveNext(PartLifecycleState nextState) at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.MoveToState(PartLifecycleState requiredState) at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.GetValueReadyToExpose() at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.<>c__DisplayClass15_0.<GetExportedValueHelper>b__0() at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.GetValueForImportElement(RuntimePartLifecycleTracker importingPartTracker, RuntimeImport import, RuntimeExport export, Func3 lazyFactory) at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.GetValueForImportSite(RuntimePartLifecycleTracker importingPartTracker, RuntimeImport import) at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.RuntimePartLifecycleTracker.b__10_0(RuntimeImport import) at System.Linq.Enumerable.WhereSelectEnumerableIterator2.MoveNext() at System.Linq.Buffer1..ctor(IEnumerable1 source) at System.Linq.Enumerable.ToArray[TSource](IEnumerable1 source) at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.RuntimePartLifecycleTracker.CreateValue() at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.Create() at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.MoveNext(PartLifecycleState nextState) at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.MoveToState(PartLifecycleState requiredState) at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.GetValueReadyToExpose() at Microsoft.VisualStudio.Composition.ExportProvider.<>c__DisplayClass53_0.b__0() at System.Lazy1.CreateValue() at System.Lazy1.LazyInitValue() at System.Lazy1.get_Value() at Microsoft.VisualStudio.Composition.NetFxAdapters.MefV1ExportProvider.<>c__DisplayClass12_0.<UnwrapExport>b__1() at System.ComponentModel.Composition.Primitives.Export.GetExportedValueCore() at System.ComponentModel.Composition.Primitives.Export.get_Value() at System.ComponentModel.Composition.ReflectionModel.ImportingItem.Cast(Type type, Export export) at System.ComponentModel.Composition.ReflectionModel.ImportingItem.CastSingleExportToImportType(Type type, Export export) at System.ComponentModel.Composition.ReflectionModel.ImportingItem.CastExportsToSingleImportType(Export[] exports) at System.ComponentModel.Composition.ReflectionModel.ImportingItem.CastExportsToImportType(Export[] exports) at System.ComponentModel.Composition.ReflectionModel.ReflectionComposablePart.SetImport(ImportingItem item, Export[] exports) at System.ComponentModel.Composition.ReflectionModel.ReflectionComposablePart.SetImport(ImportDefinition definition, IEnumerable1 exports) at System.ComponentModel.Composition.Hosting.ImportEngine.PartManager.TrySetImport(ImportDefinition import, Export[] exports) at System.ComponentModel.Composition.Hosting.ImportEngine.TrySatisfyImportSubset(PartManager partManager, IEnumerable1 imports, AtomicComposition atomicComposition) at System.ComponentModel.Composition.Hosting.ImportEngine.TrySatisfyImportsStateMachine(PartManager partManager, ComposablePart part) at System.ComponentModel.Composition.Hosting.ImportEngine.TrySatisfyImports(PartManager partManager, ComposablePart part, Boolean shouldTrackImports) at System.ComponentModel.Composition.Hosting.ImportEngine.SatisfyImports(ComposablePart part) at System.ComponentModel.Composition.Hosting.CompositionServices.GetExportedValueFromComposedPart(ImportEngine engine, ComposablePart part, ExportDefinition definition) at System.ComponentModel.Composition.Hosting.CatalogExportProvider.GetExportedValue(CatalogPart part, ExportDefinition export, Boolean isSharedPart) at System.ComponentModel.Composition.Hosting.CatalogExportProvider.CatalogExport.GetExportedValueCore() at System.ComponentModel.Composition.Primitives.Export.get_Value() at System.ComponentModel.Composition.ExportServices.GetCastedExportedValue[T](Export export) at System.ComponentModel.Composition.ExportServices.<>c__DisplayClass02.b__1() at System.Lazy1.CreateValue() at System.Lazy1.LazyInitValue() at System.Lazy1.get_Value() at Clide.Commands.CommandManager.AddCommands() at Clide.HostImpl.Initialize() at Clide.Host.Initialize(IServiceProvider hostingPackage) at Xamarin.VisualStudio.Shell.IntegrationPackage.Initialize() at Microsoft.VisualStudio.Shell.Package.Microsoft.VisualStudio.Shell.Interop.IVsPackage.SetSite(IServiceProvider sp) --- End of stack trace from previous location where exception was thrown --- at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.MoveToState(PartLifecycleState requiredState) at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.GetValueReadyToExpose() at Microsoft.VisualStudio.Composition.ExportProvider.<>c__DisplayClass53_0.<CreateExport>b__0() at System.Lazy1.CreateValue() at System.Lazy1.LazyInitValue() at System.Lazy1.get_Value() at Microsoft.VisualStudio.Composition.ExportProvider.<>c__DisplayClass70_02.<GetExports>b__1() at System.Lazy1.CreateValue() at System.Lazy1.LazyInitValue() at System.Lazy1.get_Value() at Microsoft.VisualStudio.Composition.ExportProvider.GetExportedValueT at Microsoft.VisualStudio.ComponentModelHost.ComponentModel.GetServiceT at NuGet.PackageManagement.VisualStudio.ServiceLocator.d__101.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at NuGet.PackageManagement.VisualStudio.ServiceLocator.<>c__61.<b__6_0>d.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Microsoft.VisualStudio.Threading.JoinableTask.CompleteOnCurrentThread() at Microsoft.VisualStudio.Threading.JoinableTask1.CompleteOnCurrentThread() at Microsoft.VisualStudio.Threading.JoinableTaskFactory.Run[T](Func1 asyncMethod, JoinableTaskCreationOptions creationOptions) at Microsoft.VisualStudio.Threading.JoinableTaskFactory.Run[T](Func1 asyncMethod) at NuGet.PackageManagement.VisualStudio.ServiceLocator.GetInstance[TService]() at NuGet.PackageManagement.VisualStudio.VSSolutionManager.GetProjectFactory() at NuGet.PackageManagement.VisualStudio.VSSolutionManager.EnsureNuGetAndEnvDTEProjectCache() at NuGet.PackageManagement.VisualStudio.VSSolutionManager.OnSolutionExistsAndFullyLoaded() at NuGet.PackageManagement.VisualStudio.VSSolutionManager.OnCmdUIContextChanged(UInt32 dwCmdUICookie, Int32 fActive) --- End of stack trace from previous location where exception was thrown --- at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.MoveToState(PartLifecycleState requiredState) at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.GetValueReadyToExpose() at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.<>c__DisplayClass15_0.<GetExportedValueHelper>b__0() at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.GetValueForImportElement(RuntimePartLifecycleTracker importingPartTracker, RuntimeImport import, RuntimeExport export, Func3 lazyFactory) at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.GetValueForImportSite(RuntimePartLifecycleTracker importingPartTracker, RuntimeImport import) at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.RuntimePartLifecycleTracker.b__10_0(RuntimeImport import) at System.Linq.Enumerable.WhereSelectEnumerableIterator2.MoveNext() at System.Linq.Buffer1..ctor(IEnumerable1 source) at System.Linq.Enumerable.ToArray[TSource](IEnumerable1 source) at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.RuntimePartLifecycleTracker.CreateValue() at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.Create() at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.MoveNext(PartLifecycleState nextState) at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.MoveToState(PartLifecycleState requiredState) at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.GetValueReadyToExpose() at Microsoft.VisualStudio.Composition.ExportProvider.<>c__DisplayClass53_0.b__0() at System.Lazy1.CreateValue() at System.Lazy1.LazyInitValue() at System.Lazy1.get_Value() at Microsoft.VisualStudio.Composition.NetFxAdapters.MefV1ExportProvider.<>c__DisplayClass12_0.<UnwrapExport>b__1() at System.ComponentModel.Composition.Primitives.Export.GetExportedValueCore() at System.ComponentModel.Composition.Primitives.Export.get_Value() at System.ComponentModel.Composition.ReflectionModel.ImportingItem.Cast(Type type, Export export) at System.ComponentModel.Composition.ReflectionModel.ImportingItem.CastSingleExportToImportType(Type type, Export export) at System.ComponentModel.Composition.ReflectionModel.ImportingItem.CastExportsToSingleImportType(Export[] exports) at System.ComponentModel.Composition.ReflectionModel.ImportingItem.CastExportsToImportType(Export[] exports) at System.ComponentModel.Composition.ReflectionModel.ReflectionComposablePart.SetImport(ImportingItem item, Export[] exports) at System.ComponentModel.Composition.ReflectionModel.ReflectionComposablePart.SetImport(ImportDefinition definition, IEnumerable1 exports) at System.ComponentModel.Composition.Hosting.ImportEngine.PartManager.TrySetImport(ImportDefinition import, Export[] exports) at System.ComponentModel.Composition.Hosting.ImportEngine.TrySatisfyImportSubset(PartManager partManager, IEnumerable1 imports, AtomicComposition atomicComposition) at System.ComponentModel.Composition.Hosting.ImportEngine.TrySatisfyImportsStateMachine(PartManager partManager, ComposablePart part) at System.ComponentModel.Composition.Hosting.ImportEngine.TrySatisfyImports(PartManager partManager, ComposablePart part, Boolean shouldTrackImports) at System.ComponentModel.Composition.Hosting.ImportEngine.SatisfyImportsOnce(ComposablePart part) at System.ComponentModel.Composition.Hosting.CompositionContainer.SatisfyImportsOnce(ComposablePart part) at Microsoft.VisualStudio.Composition.NetFxAdapters.CompositionService.SatisfyImportsOnce(ComposablePart part) at System.ComponentModel.Composition.AttributedModelServices.SatisfyImportsOnce(ICompositionService compositionService, Object attributedPart) at Microsoft.Web.Editor.ComponentLocator1.Import() at Microsoft.VisualStudio.JSON.Package.Completion.CompletionProviders.ProjectJSON.ProjectJSONHelpers.d__20.MoveNext() at Microsoft.VisualStudio.JSON.Package.Completion.CompletionProviders.ProjectJSON.ProjectJSONHelpers.GetRemotePackageSources() at Microsoft.VisualStudio.JSON.Package.Completion.CompletionProviders.ProjectJSON.ProjectJSONHelpers.GetPackageVersionsSearchResults(IEnumerable`1 frameworks, String packageId) at Microsoft.VisualStudio.JSON.Package.Completion.CompletionProviders.ProjectJSON.DependenciesValueCompletionProvider.GetListEntries(JSONCompletionContext context) at Microsoft.JSON.Editor.Completion.JSONCompletionSource.<>c__DisplayClass3_1.b__0() at Microsoft.Web.Editor.Utility.GuardedOperations.InvokeExtensionPoint(Object errorSource, Action action)