无法加载文件或程序集“ Microsoft.Build.Framework”(VS2017)

I believe I had the same issue as you did. I didn't save the whole error message, but my error message was

'Could not load file or assembly 'Microsoft.Build.Framework, Version=15.1.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified.'

I am using Visual Studio 2017 and was trying to do Update-Database after Add-Migration.

To resolve the issue I closed Visual Studio and re-opened it, then re-ran Update-Database again.

This may or may not resolve your issue, but I thought I'd post just in case it would help.

The root cause of this problem comes from relative paths in the devenv.exe.config file to Microsoft.Build.Framework.dll (see xml tags).

Some Visual Studio Extensions are changing the current directory and makes relative paths invalid.

To fix it, open this file in the C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\Common7\IDE\ directory. and replace all ..\..\MSBuild\15.0\Bin\ by C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\15.0\Bin\.

We had this issue, and here is what we needed to do in our case:

Problem was that we had a database command interceptor (IDbCommandInterceptor) configured that called HttpRuntime.Cache["somekey"], and for some reason migration commands failed to run because of this. After removing this depencency, all commands ran perfect. Maybe HttpRuntime weren't able to find the Build Framework dll?

So check the entire callstack when migration commands fails to see if you have a similar problem.

I've found a workaround that seems to resolve the issue for good, at least on my environment running VS 2017 Professional 15.5.2 and Entity Framework 6.1.1.

Basically, install the DLL (with a few related ones) into the GAC (Global Assembly Cache) and the issue will go away.

Follow these steps:

1. Close all running instances of Visual Studio 2017

2. Launch the Visual Studio 2017 Developer Command Prompt

3. Type the following commands (replace Professional with your edition, either Enterprise or Community, or adjust the path accordingly):

gacutil /i "C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\15.0\Bin\Microsoft.Build.Framework.dll"


gacutil /i "C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\15.0\Bin\Microsoft.Build.dll"


gacutil /i "C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\15.0\Bin\Microsoft.Build.Engine.dll"


gacutil /i "C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\15.0\Bin\Microsoft.Build.Conversion.Core.dll"


gacutil /i "C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\15.0\Bin\Microsoft.Build.Tasks.Core.dll"


gacutil /i "C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\15.0\Bin\Microsoft.Build.Utilities.Core.dll"

4. Restart Visual Studio 2017

In essence, the GAC will (in most cases) be given priority when .NET is trying to load a DLL and the FileNotFoundException will go away as your DLL will now be resolved through the GAC.

Again, it works for me and it's simply a workaround, it won't solve the core issue itself but at least I don't have to restart VS all the time when trying to work with EF migrations, and that's good enough for me.

Just in case restarting Visual Studio does not work Go to Task Manager/ Process Explorer and skill VBCSCompiler.exe

Suggest using Process Explorer

My missing file or assembly version is different with the question.

I have this error when I tried to publish my ASP.net project

Microsoft.Build.Framework, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a

I solved the problem by installing Microsoft Build Tools 2015

I think my problem caused by I publish project that was built with VS 2015 in VS 2017. Hope can help others that have same problem.

Closing and re-opening Visual Studio works like a charm!

Thanks to those who already posted. My situation was solved by a combination of the above. I have had several version of Visual Studio: 2015, 2017, 2019. At some point the version of MSBUILD went from 15.1 to 15.9, and I solved this issue by updating the C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\Common7\IDE\devenv.exe.config file to point to the 15.9 library. Here is an example of one of the entries:

<dependentAssembly>
<assemblyIdentity name="Microsoft.Build.Utilities.Core" publicKeyToken="b03f5f7f11d50a3a" culture="neutral"/>
<bindingRedirect oldVersion="2.0.0.0-99.0.0.0" newVersion="15.9.0.0"/>
<codeBase version="15.9.0.0" href="..\..\MSBuild\15.0\Bin\Microsoft.Build.Utilities.Core.dll" />
</dependentAssembly>

I've faced with same issue when updated XCode/Mono components on macOS.

Solution is to update Visual Studio for Mac to latest version.

I think that issue cause in using new MSBuild tools from .NET Core 3.0 package which installed with new XCode/Mono version.

In my case, something (maybe a NuGet-Update) did add an AssemblyBinding into the web.config-File:

<dependentAssembly>
<assemblyIdentity name="Microsoft.Build.Framework" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
<bindingRedirect oldVersion="0.0.0.0-15.1.0.0" newVersion="15.1.0.0" />
</dependentAssembly>

After removing that dependentAssemby-Entry, I could Publish the Project again.

Our local build script was using an older version of nuget.exe (4.7.1.5393) to restore NuGet packages. We started getting this error after updating to Visual Studio 2019 version 16.5.0. Updating to the latest version of nuget.exe (5.4.0.6315) fixed the issue for us.

nuget.exe can be downloaded here: https://www.nuget.org/downloads.

This worked for me - appears to be a non-support issue beginning in 2020.

In the Azure Build Pipeline > NuGet tool installer step, change Version of NuGet.exe to install to a newer version, like 5.4.0. Check versions at https://dist.nuget.org/tools.json.

Issue disappeared and now builds successfully.

This worked for me: The error occurs when I execute the nuget restore command. Nuget version 4.6.2. I have two ways to solve this problem.

Use Nuget 4.8.2 and higher. gacutil /i "C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\MSBuild\Current\Bin\Microsoft.Build.Framework.dll

After trying all of the above methods and more - running WCF app still failed for me. Error: Could not load file or assembly 'Microsoft.Build.Framework, Version=15.1.0.0..

note: tried Restarting VS, PC, killing processes, cleaning up the VS caches, nuget caches, obj, bin, .vs, packages folders

What worked for me is removing the projects' *.csproj.user file.. Apparently it had some obsolete configuration in it. Lost 4 hours trying to figure it out..

I did a restart, following which I found that the local web service I have been running was blocked by another process which had taken that port. I checked the process running and and killed the process using TCPView and all seemed to start working again.

I had this part in my web.config and simply removed it and then it start working :)

<compilation debug="true" targetFramework="4.5.2">
<assemblies>
<add assembly="Microsoft.Build.Framework, Version=14.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A"/>
</assemblies>
</compilation>

Calling "MSBuildLocator.RegisterDefaults();" before DLLs are accessed worked for me.

Problem: Could not load file or assembly 'Microsoft.Build.Framework...

Solution: I had Microsoft.Build.Framework Nuget package referenced in my project and setting the reference for this NuGet package's Copy Local to True, issue was resolved for me.

In my Roslyn project, referencing the NuGet Package Microsoft.Build.Locator and calling MSBuildLocator.RegisterDefaults(); before creating the MSBuildWorkspace solved this problem.

I had to install visual studio with the .NET cross-platform development option. I did also get universal windows platform development too

https://learn.microsoft.com/en-us/visualstudio/install/install-visual-studio?view=vs-2022

On macOS with .NET 6, I started seeing this error after upgrading form 6.0.1 to 6.0.2. The fix is to uninstall and reinstall dotnet-ef cli:

dotnet tool uninstall --global dotnet-ef
dotnet tool install --global dotnet-ef

The OP doesn't include any of the stack trace as part of the exception, but in my case there was a reference in the call stack to my version of the DbContext class.

In the constructor I check the environment to see if we're running on Live. This is because I don't want to throw exceptions if the migrations aren't up to date.

However, in order to do this check it looks up a custom section of the web.config. And, during run time this code creates an "instance" of this custom section, so that the environment can be referred to in various areas of the code.

I don't know whether it's the custom section of the web.config or the way the static "instance" is created in my code, but it seems that this is the root of my exception.

Wrapping it in a #if !DEBUG statement ensures that the PackageManager doesn't trigger this code (which is unnecessary anyway) and I no longer get the exception.

My recommendation would be to strip back your DbContext. If you are using a custom constructor, empty it and test whether it works.

I've experienced the same issue developing with .Net 6 but I've fixed it by installing from NuGet Packages Management Microsoft.Build.Framework.