Visual Studio 2022 assembly references missing

Question

Visual Studio 2022 assembly references missing

Richard Cumming 11

I have vs2019 Professional v16.11.10 and vs2022 Professional v17.0.6 installed on my machine.

When trying to use vs2022, starting a new project or loading a project that works in 2019, no references are loading. When trying to view project settings I get the following error:

Could not resolve mscorlib for target framework '.NETCoreApp,Version=v6.0'. This can happen if the target framework is not installed or if the framework moniker is incorrectly formatted.

I have tried with .net 5 and 4.8, I have repaired. I have uninstalled and reinstalled.

vs2022 just doesn't want to work.

Need some help please.

Richard Cumming 11 Reputation points

2022-02-09T21:02:59.29+00:00

I have also tried reinstalling frameworks. I have also tried running vs2022 administrator. When I start a new project and select either core 3.1, .net 5 or .net 6 as a framework then references don't load.

If I start a new project and selct .net 4.8 then the references seem fine in the solution explorer window but a build and run just fails with no error messages.

Even trying to Clean the project or solution fails.
Karen Payne MVP 35,586 Reputation points Volunteer Moderator

2022-02-10T00:08:17.913+00:00

Make sure .NET Core 5 and 6 are installed using PowerShell command dotnet --list-sdks. Seems they should be installed but better to check.

Using Windows Explorer or PowerShell, traverse to the root of the project and execute dotnet restore then back in Visual Studio perform a project rebuild. If that does not work then unload the project, reload.
Lex Li 6,037 Reputation points Microsoft Employee

2022-02-14T05:43:22.263+00:00

Unless you share the entire source code (including project files), this is not something worth discussing. Assembly references are only valid for legacy projects targeting .NET Framework. .NET Core or SDK style projects use package references.

2 answers

Your answer

Richard Cumming 11 Reputation points

2022-02-09T21:02:59.29+00:00

I have also tried reinstalling frameworks. I have also tried running vs2022 administrator. When I start a new project and select either core 3.1, .net 5 or .net 6 as a framework then references don't load.

If I start a new project and selct .net 4.8 then the references seem fine in the solution explorer window but a build and run just fails with no error messages.

Even trying to Clean the project or solution fails.
Karen Payne MVP 35,586 Reputation points Volunteer Moderator

2022-02-10T00:08:17.913+00:00

Make sure .NET Core 5 and 6 are installed using PowerShell command dotnet --list-sdks. Seems they should be installed but better to check.

Using Windows Explorer or PowerShell, traverse to the root of the project and execute dotnet restore then back in Visual Studio perform a project rebuild. If that does not work then unload the project, reload.
Lex Li 6,037 Reputation points Microsoft Employee

2022-02-14T05:43:22.263+00:00

Unless you share the entire source code (including project files), this is not something worth discussing. Assembly references are only valid for legacy projects targeting .NET Framework. .NET Core or SDK style projects use package references.

Answer 1

Sreeju Nair 12,666

I believe this is because of the missing SDK. Can you install .Net 6 SDK from the below link and try.

https://dotnet.microsoft.com/en-us/download/visual-studio-sdks

Amitesh Srivastava 1 Reputation point Microsoft Employee

2022-10-06T17:26:30.723+00:00

I installed the .net 6 sdk for x64, restarted my laptop and then ran visual studio 22 again in administrator mode. Upon running build, I still get the same errors about the missing assembly references. Additionally, I'm unable to find anything called 'assembly references' anywhere in visual studio 22 to look at the details and add the references and/or change target as was suggested on stackoverflow in a few places.
Right clicking on solution gives no such option.
Tianyu Sun-MSFT 34,441 Reputation points Microsoft External Staff

2022-10-07T06:25:49.787+00:00

Hi @Amitesh Srivastava ,

Sometimes this issue is caused by antivirus software. Are you using any antivirus software? If so, could you try to disable them temporarily > reboot your machine and check again?

Answer 2

Reza Mortazavi 1

This seems not to be a SDK issue. For me this happens just in one project among several projects in one single solution.
the problem happened when I updated a Nuget package and it failed because of error in references in that specific project, then I cleaned solution and all system and non-system references on that project got yellow signs.
I tried whatever solution I saw online none of them worked, as the last resort I renamed old project, created new one and moved items to it.

Any idea of a better solution?

Tianyu Sun-MSFT 34,441 Reputation points Microsoft External Staff

2022-11-07T06:37:38.863+00:00

Hi @Reza Mortazavi ,

Do you still remember what has changed before these warnings appeared? Does right-clicking your project > Unload project > right-click it again > Reload project work?
Reza Mortazavi 1 Reputation point

2022-11-07T12:31:31.537+00:00

Hi @Tianyu Sun-MSFT
I tried unload/reload project, close/open solution, close/run VS, updating NET SDK, and restarting computer.

I remember what happened because it happened during last 2 days twice for 2 different projects. It happened as I mentioned above, nothing out of ordinary:
Uninstalling and reinstalling System.Text.Json on a project, then all it's references got yellow signs and errors.

All projects are .NET 4.8.
Tianyu Sun-MSFT 34,441 Reputation points Microsoft External Staff

2022-11-07T13:39:50.687+00:00

Hi @Reza Mortazavi ,

Are the uninstalled System.Text.Json and the reinstalled System.Text.Json packages the same version? Does restoring NuGet packages work? Besides, no other or invalid package sources set in Tools > Options > NuGet Package Manager > Package Sources, right?
Reza Mortazavi 1 Reputation point

2022-11-08T05:51:22.35+00:00

Absolutely. To be more precise, the exact version project required which appeared in output log. But, I don't think it's System.Text.Json thing, it can be any given package.
And yes, it's the default location which is https://www.nuget.org/api/v2/

More info:
The project we talk about is a shared project used by other solutions.
All shared projects physically reside in a specific folder.
Each solution contains some solution specific projects and some shared projects.
Sometimes a package update on a shared project may occur when it's open in, let's say, Solution1, then in other solutions we just consolidate packages.

There is something which needs more investigation (hopefully next time) and that's the way each package is referred and addressed inside .csproj file. I noticed some packages of a shared project may be addressed in a solution, let's say, Solution1, while we are actually working in Solution2.

<Reference Include="System.Text.Json, Version=6.0.0.6, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51, processorArchitecture=MSIL">
<HintPath>......\Vs17\Solution1\packages\System.Text.Json.6.0.6\lib\net461\System.Text.Json.dll</HintPath>
<Private>True</Private>
</Reference>

I'm not sure yet but maybe, we have removed Solution1 and the initial problem occurred, then uninstalling and reinstalling that package has cause a crash on all system/non-system references. For now this is still a blind guess.
Tianyu Sun-MSFT 34,441 Reputation points Microsoft External Staff

2022-11-08T07:27:24.6+00:00
Hi @Reza Mortazavi ,

The situation doesn’t look to be simple. If you can share us a minimum reproducible sample, it will be more helpful to figure this issue out.

I have several suggestions currently:

Check the project file(.csproj) maybe Solution2’s, and make sure that all listed system references and package references are set with correct HintPath/path and they exist or can be found by following the path information. Just to make sure that there are no invalid references or paths saved in project file.

Since creating a new project and moving the items to it work, I may suggest you try to compare this two projects’ project file(.csproj file), and also compare the cache files/folders in the solution folder.

Clean and restore NuGet packages(cache).

Add some necessary package sources if some packages were from other package sources.

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Visual Studio 2022 assembly references missing

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