Since updating to Preview 5, I'm getting a build error for all projects:
System.Exception: An exception was thrown in the remote environment: System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> Microsoft.Build.Exceptions.InvalidProjectFileException: SDK Resolver Failure: "The SDK resolver "NuGetSdkResolver" failed while attempting to resolve the SDK "Microsoft.NET.Sdk". Exception: "System.ArgumentNullException: Value cannot be null.
Parameter name: path
at System.IO.Directory.GetParent(String path)
at Microsoft.Build.NuGetSdkResolver.GlobalJsonReader.GetMSBuildSdkVersions(SdkResolverContext context)
at Microsoft.Build.NuGetSdkResolver.NuGetSdkResolver.Resolve(SdkReference sdkReference, SdkResolverContext resolverContext, SdkResultFactory factory)
at Microsoft.Build.BackEnd.SdkResolution.SdkResolverService.ResolveSdk(Int32 submissionId, SdkReference sdk, LoggingContext loggingContext, ElementLocation sdkReferenceLocation, String solutionPath, String projectPath, Boolean interactive, Boolean isRunningInVisualStudio)""
at Microsoft.Build.Shared.ProjectErrorUtilities.ThrowInvalidProject(String errorSubCategoryResourceName, IElementLocation elementLocation, String resourceName, Object[] args)
at Microsoft.Build.Shared.ProjectErrorUtilities.ThrowInvalidProject[T1](IElementLocation elementLocation, String resourceName, T1 arg0)
at Microsoft.Build.Evaluation.Evaluator`4.ExpandAndLoadImportsFromUnescapedImportExpressionConditioned(String directoryOfImportingFile, ProjectImportElement importElement, List`1& projects, SdkResult& sdkResult, Boolean throwOnFileNotExistsError)
at Microsoft.Build.Evaluation.Evaluator`4.ExpandAndLoadImports(String directoryOfImportingFile, ProjectImportElement importElement, SdkResult& sdkResult)
at Microsoft.Build.Evaluation.Evaluator`4.EvaluateImportElement(String directoryOfImportingFile, ProjectImportElement importElement)
at Microsoft.Build.Evaluation.Evaluator`4.PerformDepthFirstPass(ProjectRootElement currentProjectOrImport)
at Microsoft.Build.Evaluation.Evaluator`4.Evaluate()
at Microsoft.Build.Evaluation.Evaluator`4.Evaluate(IEvaluatorData`4 data, ProjectRootElement root, ProjectLoadSettings loadSettings, Int32 maxNodeCount, PropertyDictionary`1 environmentProperties, ILoggingService loggingService, IItemFactory`2 itemFactory, IToolsetProvider toolsetProvider, ProjectRootElementCacheBase projectRootElementCache, BuildEventContext buildEventContext, ISdkResolverService sdkResolverService, Int32 submissionId, EvaluationContext evaluationContext, Boolean interactive)
at Microsoft.Build.Evaluation.Project.ProjectImpl.Reevaluate(ILoggingService loggingServiceForEvaluation, ProjectLoadSettings loadSettings, EvaluationContext evaluationContext)
at Microsoft.Build.Evaluation.Project.ProjectImpl.ReevaluateIfNecessary(ILoggingService loggingServiceForEvaluation, ProjectLoadSettings loadSettings, EvaluationContext evaluationContext)
at Microsoft.Build.Evaluation.Project.ProjectImpl.Initialize(IDictionary`2 globalProperties, String toolsVersion, String subToolsetVersion, ProjectLoadSettings loadSettings, EvaluationContext evaluationContext)
at Microsoft.Build.Evaluation.Project..ctor(XmlReader xmlReader, IDictionary`2 globalProperties, String toolsVersion, String subToolsetVersion, ProjectCollection projectCollection, ProjectLoadSettings loadSettings)
at Microsoft.Build.Evaluation.Project..ctor(XmlReader xmlReader, IDictionary`2 globalProperties, String toolsVersion, ProjectCollection projectCollection, ProjectLoadSettings loadSettings)
at nCrunch.VSIntegration2010.MSBuildIntegration.BuildableProject2010.Initialise(BuildXml buildXml, FilePath projectFilePath, IDictionary`2 globalProperties)
at nCrunch.Compiler.RemoteBuildRunner.AnalyseComponentBuild(ComponentLoadParameters parameters)
--- End of inner exception stack trace ---
at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor)
at System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments)
at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
at nCrunch.TaskRunner.Ipc.IpcMessageProcessor.(CallMethodMessage )
at nCrunch.TaskRunner.Ipc.IpcMessageProcessor.ProcessMessageReturningResult(Byte[] data)
at nCrunch.TaskRunner.Ipc.RemoteInstance.(Byte[] )
at nCrunch.TaskRunner.Ipc.RemoteInstance.Invoke(IMessage msg)
at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)
at nCrunch.Compiler.IRemoteBuildRunner.AnalyseComponentBuild(ComponentLoadParameters parameters)
at nCrunch.Core.BuildManagement.BuildProcessLauncher..(IRemoteBuildRunner )
at nCrunch.Core.BuildManagement.BuildProcessLauncher.(Action`1 , FilePath , String , ExternalProcess )
at nCrunch.Core.BuildManagement.BuildProcessLauncher.(Action`1 , EffectiveProcessorArchitecture , GridClientId , BuildSystemParameters , IList`1 , Nullable`1 , GridAddress )
at nCrunch.Core.BuildManagement.BuildProcessLauncher.AnalyseComponentBuildInExternalProcess(ComponentLoadParameters parameters, IList`1 customEnvironmentVariables)
at nCrunch.Client.ComponentLoader.SnapshotComponentLoader.(EffectiveProcessorArchitecture , String )
at nCrunch.Client.ComponentLoader.SnapshotComponentLoader.CreateComponentFromXml(FilePath projectFilePath, ParsedBuildXml projectXml, FilePath solutionFilePath, String[] additionalFilesToIncludeAtSolutionLevel, Boolean isLoadedFromFile, VisualStudioVersion vsVersion, ComponentUniqueName componentName, TaskSettings componentTaskSettings, Exception parseException, String targetFrameworkForMsbuild, String visibleTargetFramework)
I've sent through a bug report via the menu also if that helps.