Error with VS 16.5.X "Project system data flow DataflowBlockSlim"

Question

Getting this error when building solution just after upgrading to VS 16.5.4. Nothing has changed on current machine.

Update to 16.5.5 and 16.6.2 did NOT solve the issue BUT 16.7 DID ! finally

Update ON 13/07/2020 : Apparently will be solve into 16.7 version hopefully https://developercommunity.visualstudio.com/comments/1042100/view.html

How can i solve it ?

Information:

Microsoft Visual Studio Enterprise 2019 Version 16.5.4 VisualStudio.16.Release/16.5.4+30011.22 Microsoft .NET Framework Version 4.8.03752

Installed Version: Enterprise

Architecture Diagrams and Analysis Tools 00435-60000-00000-AA704 Microsoft Architecture Diagrams and Analysis Tools

Visual C++ 2019 00435-60000-00000-AA704 Microsoft Visual C++ 2019

Add New File 3.5.138 The fastest and easiest way to add new files to any project - including files that start with a dot

ADL Tools Service Provider 1.0 This package contains services used by Data Lake tools

ASA Service Provider 1.0

ASP.NET and Web Tools 2019 16.5.236.49856 ASP.NET and Web Tools 2019

ASP.NET Web Frameworks and Tools 2019 16.5.236.49856 For additional information, visit https://www.asp.net/

Azure App Service Tools v3.0.0 16.5.236.49856 Azure App Service Tools v3.0.0

Azure Data Lake Node 1.0 This package contains the Data Lake integration nodes for Server Explorer.

Azure Data Lake Tools for Visual Studio 2.4.6000.1 Microsoft Azure Data Lake Tools for Visual Studio

Azure Functions and Web Jobs Tools 16.5.236.49856 Azure Functions and Web Jobs Tools

Azure Stream Analytics Tools for Visual Studio 2.4.6000.1 Microsoft Azure Stream Analytics Tools for Visual Studio

C# Tools 3.5.0-beta4-20153-05+20b9af913f1b8ce0a62f72bea9e75e4aa3cf6b0e C# components used in the IDE. Depending on your project type and settings, a different version of the compiler may be used.

Common Azure Tools 1.10 Provides common services for use by Azure Mobile Services and Microsoft Azure Tools.

EditorConfig Language Service 1.17.284 Language service for .editorconfig files.

EditorConfig helps developers define and maintain consistent coding styles between different editors and IDEs.

File Nesting 2.6.85 Automatically nest files based on file name and enables developers to nest and unnest any file manually

GitHub.VisualStudio 2.11.96.24460 A Visual Studio Extension that brings the GitHub Flow into Visual Studio.

Indent Guides 16 Indent Guides

Adds visual guides at each indentation level.

IntelliCode Extension 1.0 IntelliCode Visual Studio Extension Detailed Info

Markdown Editor 1.12.253 A full featured Markdown editor with live preview and syntax highlighting. Supports GitHub flavored Markdown.

Microsoft Azure HDInsight Azure Node 2.4.6000.1 HDInsight Node under Azure Node

Microsoft Azure Hive Query Language Service 2.4.6000.1 Language service for Hive query

Microsoft Azure Stream Analytics Language Service 2.4.6000.1 Language service for Azure Stream Analytics

Microsoft Azure Stream Analytics Node 1.0 Azure Stream Analytics Node under Azure Node

Microsoft Azure Tools 2.9 Microsoft Azure Tools for Microsoft Visual Studio 2019 - v2.9.30207.1

Microsoft Continuous Delivery Tools for Visual Studio 0.4 Simplifying the configuration of Azure DevOps pipelines from within the Visual Studio IDE.

Microsoft JVM Debugger 1.0 Provides support for connecting the Visual Studio debugger to JDWP compatible Java Virtual Machines

Microsoft Library Manager 2.1.25+gdacdb9b7a1 Install client-side libraries easily to any web project

Microsoft MI-Based Debugger 1.0 Provides support for connecting Visual Studio to MI compatible debuggers

Microsoft Visual C++ Wizards 1.0 Microsoft Visual C++ Wizards

Microsoft Visual Studio Tools for Containers 1.1 Develop, run, validate your ASP.NET Core applications in the target environment. F5 your application directly into a container with debugging, or CTRL + F5 to edit & refresh your app without having to rebuild the container.

Microsoft Visual Studio VC Package 1.0 Microsoft Visual Studio VC Package

NuGet Package Manager 5.5.0 NuGet Package Manager in Visual Studio. For more information about NuGet, visit https://docs.nuget.org/

Open Command Line 2.4.226 2.4.226

ProjectServicesPackage Extension 1.0 ProjectServicesPackage Visual Studio Extension Detailed Info

Snapshot Debugging Extension 1.0 Snapshot Debugging Visual Studio Extension Detailed Info

SQL Server Data Tools 16.0.62003.05170 Microsoft SQL Server Data Tools

ToolWindowHostedEditor 1.0 Hosting json editor into a tool window

TSVN 1.9 Control TortoiseSVN from within Visual Studio

TypeScript Tools 16.0.20225.2001 TypeScript Tools for Microsoft Visual Studio

Visual Basic Tools 3.5.0-beta4-20153-05+20b9af913f1b8ce0a62f72bea9e75e4aa3cf6b0e Visual Basic components used in the IDE. Depending on your project type and settings, a different version of the compiler may be used.

Visual F# Tools 10.8.0.0 for F# 4.7 16.5.0-beta.20181.6+85af456066acd4e76d2bc7821b44a325e46f2fca Microsoft Visual F# Tools 10.8.0.0 for F# 4.7

Visual Studio Code Debug Adapter Host Package 1.0 Interop layer for hosting Visual Studio Code debug adapters in Visual Studio

Visual Studio Container Tools Extensions (Preview) 1.0 View, manage, and diagnose containers within Visual Studio.

Visual Studio Tools for Containers 1.0 Visual Studio Tools for Containers

Visual Studio Tools for Kubernetes 1.0 Visual Studio Tools for Kubernetes

System.AggregateException: Project system data flow 'DataflowBlockSlim (ActionBlockSlimAsync`1 : 19600903)' closed because of an exception: System.AggregateException: One or more errors occurred. ---> System.InvalidOperationException: Unexpected false
  at Roslyn.Utilities.Contract.ThrowIfFalse(Boolean condition, String message)
  at Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem.CPS.CPSProject.EndBatch()
  at Microsoft.VisualStudio.ProjectSystem.LanguageServices.WorkspaceProjectContextHost.WorkspaceProjectContextHostInstance.<ApplyProjectChangesUnderLockAsync>d__19.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.ReentrantSemaphore.StackSemaphore.<>c__DisplayClass3_0.<<ExecuteAsync>b__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.AwaitExtensions.ExecuteContinuationSynchronouslyAwaiter.GetResult()
  at Microsoft.VisualStudio.Threading.ReentrantSemaphore.StackSemaphore.<ExecuteAsync>d__3.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.ProjectSystem.OnceInitializedOnceDisposedUnderLockAsync.<ExecuteUnderLockCoreAsync>d__7.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.ProjectSystem.DataReceivingBlockSlim`1.<ProcessInputQueueAsync>d__5.MoveNext()
  --- End of inner exception stack trace ---
---> (Inner Exception #0) System.InvalidOperationException: Unexpected false
  at Roslyn.Utilities.Contract.ThrowIfFalse(Boolean condition, String message)
  at Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem.CPS.CPSProject.EndBatch()
  at Microsoft.VisualStudio.ProjectSystem.LanguageServices.WorkspaceProjectContextHost.WorkspaceProjectContextHostInstance.<ApplyProjectChangesUnderLockAsync>d__19.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
 
--- 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.ProjectSystem.OnceInitializedOnceDisposedUnderLockAsync.<ExecuteUnderLockCoreAsync>d__7.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.ProjectSystem.DataReceivingBlockSlim`1.<ProcessInputQueueAsync>d__5.MoveNext()<---
. ---> System.InvalidOperationException: Unexpected false
  at Roslyn.Utilities.Contract.ThrowIfFalse(Boolean condition, String message)
  at Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem.CPS.CPSProject.EndBatch()
  at Microsoft.VisualStudio.ProjectSystem.LanguageServices.WorkspaceProjectContextHost.WorkspaceProjectContextHostInstance.<ApplyProjectChangesUnderLockAsync>d__19.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.ReentrantSemaphore.StackSemaphore.<>c__DisplayClass3_0.<<ExecuteAsync>b__0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---

  at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
  at Microsoft.VisualStudio.ProjectSystem.OnceInitializedOnceDisposedUnderLockAsync.<ExecuteUnderLockCoreAsync>d__7.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.ProjectSystem.DataReceivingBlockSlim`1.<ProcessInputQueueAsync>d__5.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
  at Microsoft.VisualStudio.ProjectSystem.CommonProjectSystemTools.Rethrow(Exception ex)
  at Microsoft.VisualStudio.ProjectSystem.ProjectErrorReporting.<>c__DisplayClass6_0.<SubmitErrorReport>b__0()
  at Microsoft.VisualStudio.ProjectSystem.ExceptionFilter.<>c__DisplayClass2_0.<Guard>g__action|0()
  at GuardMethodClass.GuardMethod(Func`1 , Func`2 , Func`2 )
  --- End of inner exception stack trace ---
---> (Inner Exception #0) System.InvalidOperationException: Unexpected false
  at Roslyn.Utilities.Contract.ThrowIfFalse(Boolean condition, String message)
  at Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem.CPS.CPSProject.EndBatch()
  at Microsoft.VisualStudio.ProjectSystem.LanguageServices.WorkspaceProjectContextHost.WorkspaceProjectContextHostInstance.<ApplyProjectChangesUnderLockAsync>d__19.MoveNext()
--- End of stack trace from previous location where exception was thrown ---

--- End of stack trace from previous location where exception was thrown ---
  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
  at Microsoft.VisualStudio.ProjectSystem.CommonProjectSystemTools.Rethrow(Exception ex)
  at Microsoft.VisualStudio.ProjectSystem.ProjectErrorReporting.<>c__DisplayClass6_0.<SubmitErrorReport>b__0()
  at Microsoft.VisualStudio.ProjectSystem.ExceptionFilter.<>c__DisplayClass2_0.<Guard>g__action|0()
  at GuardMethodClass.GuardMethod(Func`1 , Func`2 , Func`2 )<---

Answer 1

Not sure if this is your issues, but after looking around it looks like my previous MSBuild and related assemblies were registered in the GAC. Once I ran this in an elevated VS developer command prompt: "gacutil /u Microsoft.Build.Framework"

All of my issues went away.

Got this solution from here: https://developercommunity.visualstudio.com/content/problem/952614/after-update-from-vs-2019-1645-to-vs-2019-165-gett.html

Answer 2

There is an open ticket on M$ Developer community: https://developercommunity.visualstudio.com/content/problem/992414/project-system-data-flow-dataflowblockslim-actionb.html.