Visual Studio 2022 - could not load file or assembly Microsoft.Build.Tasks.v4.0. The system cannot f-CodePudding

So I'm back from a nice Christmas break - and completely stymied. When I try to build my Visual Studio 2022 solution I get this message:

Build (web): Could not load file or assembly 'Microsoft.Build.Tasks.v4.0, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified.

I also get this in VS 2019 too. My website is ASP.NET webforms - I've got two other MVC websites which build and run perfectly. Here is the relevant section of my web.config file:

<compilation debug="true" strict="true" explicit="true" batch="false" targetFramework="4.7.2">
      <assemblies>
        <add assembly="System.Data.Entity.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
        <add assembly="System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
        <add assembly="System.Printing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
        <add assembly="System.Security, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A" />
        <add assembly="System.Data.Entity.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
        <add assembly="Microsoft.CSharp, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A" />
        <add assembly="Microsoft.Build.Framework, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A" />
        <add assembly="System.Xaml, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
      </assemblies>

I've just spent 3 hours reading through blogs like this StackOverflow one:

I've had this sort of problem on numerous other occasions, and usually sorted it fairly quickly - but not this time. I know little about building projects - I just want Visual Studio to do it all for me!

Can any kind person help please?

CodePudding user response：

As the error said, Microsoft.Build.Tasks.v4.0 could not be found.

Have you tried adding this reference? instead of Microsoft.Build.Framework.

CodePudding user response：

So I've at least got this in a working state - here's an update for anyone else facing this nightmare (and who, like me, doesn't fully understand what building involves).

I still have the build error, but if I right-click on a .aspx file to view it in a browser this now works (before it gave a compilation error). To reach this state I removed any references to any Microsoft.Build libraries that I had set in Nuget. I don't know whether this helped or not!

Of course I can't debug (because this requires a build), so this is at best a temporary fix, but at least I can do some work on the website.