Unexpected error detected. Check the Tests Output Pane for details.

When I build any project in my solution, message "Unexpected error detected. Check the Tests Output Pane for details." appear on bottom on vs window. The test explorer window is empty (no tests, although later all works).

In output window, for show output from : Tests  - this error

System.ArgumentNullException: Value cannot be null.Parameter name: source  at Microsoft.VisualStudio.Shell.ValidateArg.NotNull[T](T arg, String parameterName)   at Microsoft.VisualStudio.Shell.ValidateArg.NotNullOrEmpty[T](IEnumerable`1 arg, String parameterName)   at Microsoft.VisualStudio.Shell.Interop.VSProjectExtensions.CompareNormalizedPath(String source, String target)   at Microsoft.VisualStudio.Shell.Interop.VSProjectExtensions.GetKeyOutputForIVsOutputGroup(IVsOutputGroup outputGroup)   at Microsoft.VisualStudio.Shell.Interop.VSProjectExtensions.GetProjectOutputPath(IVsProjectCfg2 projectConfig, String groupName)   at Microsoft.VisualStudio.Shell.Interop.VSProjectExtensions.GetKeyOutputForGroup(IVsSolutionBuildManager buildManager, IVsProject project, String groupName)   at Microsoft.VisualStudio.Shell.Interop.VSProjectExtensions.GetProjectOutputPath(IVsProject project, IServiceProvider serviceProvider)   at Microsoft.VisualStudio.TestWindow.VsAdapters.VsTestContainer.get_Source()   at Microsoft.VisualStudio.TestWindow.VsAdapters.VsTestContainer.CreateTimeStamp()   at Microsoft.VisualStudio.TestWindow.VsAdapters.VsTestContainer..ctor(ITestContainerDiscoverer discoverer, ILogger log, IVsProject project, IServiceProvider serviceProvider, IVsAppContainerUtilities appContainerUtilities)   at Microsoft.VisualStudio.TestWindow.VsAdapters.VsProjectOutputContainerDiscoverer.<get_TestContainers>b__0(IVsProject p)   at System.Linq.Enumerable.WhereSelectEnumerableIterator`2.MoveNext()   at System.Linq.Enumerable.WhereEnumerableIterator`1.MoveNext()   at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)   at Microsoft.VisualStudio.TestWindow.Controller.TestContainerDiscovererExtension.GetSortedContainers(ITestContainerDiscoverer discoverer)   at Microsoft.VisualStudio.TestWindow.Controller.TestContainerProvider.GetContainersFromDiscoverer(ITestContainerDiscoverer discoverer)