r/JetBrains_Rider

https://preview.redd.it/zshz52b3e2ah1.png?width=1808&format=png&auto=webp&s=5ebe42980432690ce1e3b7d7f75878f3bbdec7ae

Hey everyone,

I am hitting a massive, blocking issue with JetBrains Rider's Roslyn background worker while attempting to use the .NET 10 SDK on Ubuntu 26.04.

The IDE is completely failing to load almost every single code fixer, provider, and analyzer pack across the solution. Because of this, my syntax highlighting, autocomplete, and code inspections are fundamentally broken.

The Symptoms:

1. Dozens of Provider Failures: Under the Toolset, Environment problems tab, I am getting a wall of exceptions stating:
   • Failed to create provider 'Microsoft.CodeAnalysis.NetAnalyzers...'
   • Failed to create provider 'Microsoft.AspNetCore.App.CodeFixes...'
   • Failed to create provider 'Microsoft.Interop.LibraryImportGenerator...'
2. Hover Tooltips are Dead: If I hover over an external NuGet package symbol (like IRequest<> from MediatR), absolutely nothing shows up.
3. The Temporary Workaround: The only way Rider acknowledges the type is if I Ctrl + click the class to force Rider to open and decompile the source .dll. Once the decompiled file is open in a tab, Rider finally indexes it locally and hover tooltips start working for that type.

The root cause in the Rider exception pane points back to a cascading dependency failure in the background process:

Could not load file or assembly 'System.Composition.AttributedModel, Version=10.0.0.9, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. The system cannot find the file specified.

--- EXCEPTION #1/1 [FileNotFoundException]
ClassName = System.IO.FileNotFoundException
Data.ThreadLocalDebugInfo = “
endpoint `RoslynWorker.RoslynModel.projectModel.$.applyChanges`
-> Scheduler: 'RoslynWorkerScheduler' on thread `MainThread:1`
”

My Environment Specs:

• OS: Ubuntu 26.04 (SDK installed natively via system apt repositories)
• SDK CLI Path: /usr/bin/dotnet (Points to /usr/lib/dotnet/sdk/10.0.109/)
• Host Runtime Version: 10.0.9
• Rider Toolset: Configured explicitly to use the above system path and the matching MSBuild.dll from the SDK directory.

What I've tried so far:

• Manually configuring Rider's Toolset settings to point directly to the system's /usr/bin/dotnet and /usr/lib/dotnet/.../MSBuild.dll.
• Invalidating all file caches and restarting the IDE.

Hello there!

I am trying the community version of Rider , and more and less I'm finding myself comfortable with the new IDE coming from Visual Studio.

I have some credits on Openrouter and put the models from openrouter on the custom API key selection. DeepSeek 4 Pro for chat and flash for code completion into the Jetbrains AI extenstion.

The chat works flawlessly, but inline code completion doesn't work.

Is because code completion is not compatible with deepseek or it works only with Jetbrains official models?

Thank you!