[fail]: OmniSharp.MSBuild.ProjectLoader

Question

I want to learn how to code in C# using Visual Studio Code.
But when I open my project or restart OmniSharp, I will get a notification saying:

Some projects have trouble loading. Please review the output for more details.

And then, when I check the output, there are some error messages.
I think the source of those error is:

[fail]: OmniSharp.MSBuild.ProjectLoader
The SDK 'ILLink.Tasks' specified could not be found.

Just in case I'm wrong though, here is the whole output message:

Starting OmniSharp server at 25/06/2022, 01:25:26
    Target: c:\Users\Asus\Desktop\C#\1st project

OmniSharp server started.
    Path: c:\Users\Asus\.vscode\extensions\ms-dotnettools.csharp-1.25.0-win32-x64\.omnisharp\1.39.1-beta.2\OmniSharp.exe
    PID: 3408

[info]: OmniSharp.Stdio.Host
        Starting OmniSharp on Windows 6.2.9200.0 (x64)
[info]: OmniSharp.Services.DotNetCliService
        Checking the 'DOTNET_ROOT' environment variable to find a .NET SDK
[info]: OmniSharp.Services.DotNetCliService
        Using the 'dotnet' on the PATH.
[info]: OmniSharp.Services.DotNetCliService
        DotNetPath set to dotnet
[info]: OmniSharp.MSBuild.Discovery.MSBuildLocator
        Located 1 MSBuild instance(s)
            1: Visual Studio Community 2019 16.11.31911.196 16.11.2 - "C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Current\Bin"
[info]: OmniSharp.MSBuild.Discovery.MSBuildLocator
        Registered MSBuild instance: Visual Studio Community 2019 16.11.31911.196 16.11.2 - "C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Current\Bin"
[info]: OmniSharp.WorkspaceInitializer
        Invoking Workspace Options Provider: OmniSharp.Roslyn.CSharp.Services.CSharpFormattingWorkspaceOptionsProvider, Order: 0
[info]: OmniSharp.Cake.CakeProjectSystem
        Detecting Cake files in 'c:\Users\Asus\Desktop\C#\1st project'.
[info]: OmniSharp.Cake.CakeProjectSystem
        Did not find any Cake files
[info]: OmniSharp.MSBuild.ProjectSystem
        No solution files found in 'c:\Users\Asus\Desktop\C#\1st project'
[info]: OmniSharp.MSBuild.ProjectManager
        Queue project update for 'c:\Users\Asus\Desktop\C#\1st project\1st project.csproj'
[info]: OmniSharp.Script.ScriptProjectSystem
        Detecting CSX files in 'c:\Users\Asus\Desktop\C#\1st project'.
[info]: OmniSharp.Script.ScriptProjectSystem
        Did not find any CSX files
[info]: OmniSharp.WorkspaceInitializer
        Configuration finished.
[info]: OmniSharp.Stdio.Host
        Omnisharp server running using Stdio at location 'c:\Users\Asus\Desktop\C#\1st project' on host 7756.
[info]: OmniSharp.MSBuild.ProjectManager
        Loading project: c:\Users\Asus\Desktop\C#\1st project\1st project.csproj
[fail]: OmniSharp.MSBuild.ProjectLoader
        The SDK 'ILLink.Tasks' specified could not be found.
[fail]: OmniSharp.MSBuild.ProjectManager
        Failed to load project file 'c:\Users\Asus\Desktop\C#\1st project\1st project.csproj'.
Microsoft.Build.Exceptions.InvalidProjectFileException: The SDK 'ILLink.Tasks' specified could not be found.  C:\Program Files\dotnet\sdk\3.1.420\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.ILLink.targets
   at Microsoft.Build.Shared.ProjectErrorUtilities.ThrowInvalidProject(String errorSubCategoryResourceName, IElementLocation elementLocation, String resourceName, Object[] args)
   at Microsoft.Build.Evaluation.Evaluator`4.ExpandAndLoadImportsFromUnescapedImportExpressionConditioned(String directoryOfImportingFile, ProjectImportElement importElement, List`1& projects, SdkResult& sdkResult, Boolean throwOnFileNotExistsError)
   at Microsoft.Build.Evaluation.Evaluator`4.ExpandAndLoadImports(String directoryOfImportingFile, ProjectImportElement importElement, SdkResult& sdkResult)
   at Microsoft.Build.Evaluation.Evaluator`4.EvaluateImportElement(String directoryOfImportingFile, ProjectImportElement importElement)
   at Microsoft.Build.Evaluation.Evaluator`4.PerformDepthFirstPass(ProjectRootElement currentProjectOrImport)
   at Microsoft.Build.Evaluation.Evaluator`4.EvaluateImportElement(String directoryOfImportingFile, ProjectImportElement importElement)
   at Microsoft.Build.Evaluation.Evaluator`4.PerformDepthFirstPass(ProjectRootElement currentProjectOrImport)
   at Microsoft.Build.Evaluation.Evaluator`4.EvaluateImportElement(String directoryOfImportingFile, ProjectImportElement importElement)
   at Microsoft.Build.Evaluation.Evaluator`4.PerformDepthFirstPass(ProjectRootElement currentProjectOrImport)
   at Microsoft.Build.Evaluation.Evaluator`4.EvaluateImportElement(String directoryOfImportingFile, ProjectImportElement importElement)
   at Microsoft.Build.Evaluation.Evaluator`4.PerformDepthFirstPass(ProjectRootElement currentProjectOrImport)
   at Microsoft.Build.Evaluation.Evaluator`4.Evaluate()
   at Microsoft.Build.Evaluation.Evaluator`4.Evaluate(IEvaluatorData`4 data, ProjectRootElement root, ProjectLoadSettings loadSettings, Int32 maxNodeCount, PropertyDictionary`1 environmentProperties, ILoggingService loggingService, IItemFactory`2 itemFactory, IToolsetProvider toolsetProvider, ProjectRootElementCacheBase projectRootElementCache, BuildEventContext buildEventContext, ISdkResolverService sdkResolverService, Int32 submissionId, EvaluationContext evaluationContext, Boolean interactive)
   at Microsoft.Build.Evaluation.Project.ProjectImpl.Reevaluate(ILoggingService loggingServiceForEvaluation, ProjectLoadSettings loadSettings, EvaluationContext evaluationContext)
   at Microsoft.Build.Evaluation.Project.ProjectImpl.ReevaluateIfNecessary(ILoggingService loggingServiceForEvaluation, ProjectLoadSettings loadSettings, EvaluationContext evaluationContext)
   at Microsoft.Build.Evaluation.Project.ProjectImpl.ReevaluateIfNecessary(EvaluationContext evaluationContext)
   at Microsoft.Build.Evaluation.Project.ProjectImpl.Initialize(IDictionary`2 globalProperties, String toolsVersion, String subToolsetVersion, ProjectLoadSettings loadSettings, EvaluationContext evaluationContext)
   at Microsoft.Build.Evaluation.Project..ctor(String projectFile, IDictionary`2 globalProperties, String toolsVersion, String subToolsetVersion, ProjectCollection projectCollection, ProjectLoadSettings loadSettings, EvaluationContext evaluationContext)
   at Microsoft.Build.Evaluation.ProjectCollection.LoadProject(String fileName, IDictionary`2 globalProperties, String toolsVersion)
   at OmniSharp.MSBuild.ProjectLoader.EvaluateProjectFileCore(String filePath, IReadOnlyDictionary`2 projectConfigurationsInSolution, IList`1 loggers) in D:\a\1\s\src\OmniSharp.MSBuild\ProjectLoader.cs:line 160
   at OmniSharp.MSBuild.ProjectLoader.BuildProject(String filePath, IReadOnlyDictionary`2 configurationsInSolution) in D:\a\1\s\src\OmniSharp.MSBuild\ProjectLoader.cs:line 84
   at OmniSharp.MSBuild.ProjectFile.ProjectFileInfo.Load(String filePath, ProjectIdInfo projectIdInfo, ProjectLoader loader, Guid sessionId, DotNetInfo dotNetInfo) in D:\a\1\s\src\OmniSharp.MSBuild\ProjectFile\ProjectFileInfo.cs:line 117
   at OmniSharp.MSBuild.ProjectManager.<>c__DisplayClass32_0.<LoadProject>b__0() in D:\a\1\s\src\OmniSharp.MSBuild\ProjectManager.cs:line 305
   at OmniSharp.MSBuild.ProjectManager.LoadOrReloadProject(String projectFilePath, Func`1 loader) in D:\a\1\s\src\OmniSharp.MSBuild\ProjectManager.cs:line 316
c:\Users\Asus\Desktop\C#\1st project\1st project.csproj(0,0)
Microsoft.Build.Exceptions.InvalidProjectFileException: The SDK 'ILLink.Tasks' specified could not be found.  C:\Program Files\dotnet\sdk\3.1.420\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.ILLink.targets
   at Microsoft.Build.Shared.ProjectErrorUtilities.ThrowInvalidProject(String errorSubCategoryResourceName, IElementLocation elementLocation, String resourceName, Object[] args)
   at Microsoft.Build.Evaluation.Evaluator`4.ExpandAndLoadImportsFromUnescapedImportExpressionConditioned(String directoryOfImportingFile, ProjectImportElement importElement, List`1& projects, SdkResult& sdkResult, Boolean throwOnFileNotExistsError)
   at Microsoft.Build.Evaluation.Evaluator`4.ExpandAndLoadImports(String directoryOfImportingFile, ProjectImportElement importElement, SdkResult& sdkResult)
   at Microsoft.Build.Evaluation.Evaluator`4.EvaluateImportElement(String directoryOfImportingFile, ProjectImportElement importElement)
   at Microsoft.Build.Evaluation.Evaluator`4.PerformDepthFirstPass(ProjectRootElement currentProjectOrImport)
   at Microsoft.Build.Evaluation.Evaluator`4.EvaluateImportElement(String directoryOfImportingFile, ProjectImportElement importElement)
   at Microsoft.Build.Evaluation.Evaluator`4.PerformDepthFirstPass(ProjectRootElement currentProjectOrImport)
   at Microsoft.Build.Evaluation.Evaluator`4.EvaluateImportElement(String directoryOfImportingFile, ProjectImportElement importElement)
   at Microsoft.Build.Evaluation.Evaluator`4.PerformDepthFirstPass(ProjectRootElement currentProjectOrImport)
   at Microsoft.Build.Evaluation.Evaluator`4.EvaluateImportElement(String directoryOfImportingFile, ProjectImportElement importElement)
   at Microsoft.Build.Evaluation.Evaluator`4.PerformDepthFirstPass(ProjectRootElement currentProjectOrImport)
   at Microsoft.Build.Evaluation.Evaluator`4.Evaluate()
   at Microsoft.Build.Evaluation.Evaluator`4.Evaluate(IEvaluatorData`4 data, ProjectRootElement root, ProjectLoadSettings loadSettings, Int32 maxNodeCount, PropertyDictionary`1 environmentProperties, ILoggingService loggingService, IItemFactory`2 itemFactory, IToolsetProvider toolsetProvider, ProjectRootElementCacheBase projectRootElementCache, BuildEventContext buildEventContext, ISdkResolverService sdkResolverService, Int32 submissionId, EvaluationContext evaluationContext, Boolean interactive)
   at Microsoft.Build.Evaluation.Project.ProjectImpl.Reevaluate(ILoggingService loggingServiceForEvaluation, ProjectLoadSettings loadSettings, EvaluationContext evaluationContext)
   at Microsoft.Build.Evaluation.Project.ProjectImpl.ReevaluateIfNecessary(ILoggingService loggingServiceForEvaluation, ProjectLoadSettings loadSettings, EvaluationContext evaluationContext)
   at Microsoft.Build.Evaluation.Project.ProjectImpl.ReevaluateIfNecessary(EvaluationContext evaluationContext)
   at Microsoft.Build.Evaluation.Project.ProjectImpl.Initialize(IDictionary`2 globalProperties, String toolsVersion, String subToolsetVersion, ProjectLoadSettings loadSettings, EvaluationContext evaluationContext)
   at Microsoft.Build.Evaluation.Project..ctor(String projectFile, IDictionary`2 globalProperties, String toolsVersion, String subToolsetVersion, ProjectCollection projectCollection, ProjectLoadSettings loadSettings, EvaluationContext evaluationContext)
   at Microsoft.Build.Evaluation.ProjectCollection.LoadProject(String fileName, IDictionary`2 globalProperties, String toolsVersion)
   at OmniSharp.MSBuild.ProjectLoader.EvaluateProjectFileCore(String filePath, IReadOnlyDictionary`2 projectConfigurationsInSolution, IList`1 loggers) in D:\a\1\s\src\OmniSharp.MSBuild\ProjectLoader.cs:line 160
   at OmniSharp.MSBuild.ProjectLoader.BuildProject(String filePath, IReadOnlyDictionary`2 configurationsInSolution) in D:\a\1\s\src\OmniSharp.MSBuild\ProjectLoader.cs:line 84
   at OmniSharp.MSBuild.ProjectFile.ProjectFileInfo.Load(String filePath, ProjectIdInfo projectIdInfo, ProjectLoader loader, Guid sessionId, DotNetInfo dotNetInfo) in D:\a\1\s\src\OmniSharp.MSBuild\ProjectFile\ProjectFileInfo.cs:line 117
   at OmniSharp.MSBuild.ProjectManager.<>c__DisplayClass32_0.<LoadProject>b__0() in D:\a\1\s\src\OmniSharp.MSBuild\ProjectManager.cs:line 305
   at OmniSharp.MSBuild.ProjectManager.LoadOrReloadProject(String projectFilePath, Func`1 loader) in D:\a\1\s\src\OmniSharp.MSBuild\ProjectManager.cs:line 316

[fail]: OmniSharp.MSBuild.ProjectManager
        Attempted to update project that is not loaded: c:\Users\Asus\Desktop\C#\1st project\1st project.csproj

Answer 1

If you want to learn to code in c#, then i suggest to start with just pure c#. Just ask yourself why you should use omnisharp? Which case does you have? Would it be make sense to use a tool like omnisharp? If you don't have answer to these questions: Don't use the tool.

If you want to learn a new programming language stick to the basics.

Just open visual studio -> create a new project -> choose console app and experiment with the basic features in c#. After you have some clue about c#, you can try to figure out what you realy want to code. A project will give you motivation.

Did you know the song "99 Bottles of Beer"?

Try to figure out, how to code it in c#.

Anyway, if you want to stick around with omnisharp:

The failure, which you described, is an official issue .

Answer 2

Change the Omnisharp: Path in the Visual Studio Code extension by settings the C# configuration to something like this:

C:\Users\USER\\.vscode\extensions\ms-dotnettools.csharp-1.25.0-win32-x64\.omnisharp\1.39.0-net6.0\OmniSharp.exe

(This defaults to ..\..\1.39.0\OmniSharp.exe )