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.NET CLR Error — Application Has Stopped Working (CLR20r3)

Errorruntime

Overview

Fix .NET CLR errors causing application crashes with CLR20r3 event names, including missing runtime versions, corrupted assemblies, and framework conflicts.

Key Details

  • CLR20r3 is the Watson bucket event name for unhandled .NET exceptions causing crashes
  • Event Viewer shows the faulting module, exception code, and the .NET method that crashed
  • Applications may require specific .NET Framework versions (3.5, 4.7.2, 4.8) or .NET 6/7/8 runtime
  • Missing or corrupted .NET runtime installations are a common cause
  • Side-by-side .NET installations can conflict if the application targets a specific version

Common Causes

  • Required .NET Framework or .NET runtime version not installed
  • .NET runtime corrupted by a failed Windows Update or incomplete installation
  • Application targeting a newer .NET version than what is installed
  • Missing Visual C++ Redistributable required by native dependencies

Steps

  1. 1Check Event Viewer > Application log for the CLR20r3 event details and exception information
  2. 2Install the required .NET version: check the application's documentation or error details
  3. 3Install .NET Framework 3.5: Settings > Apps > Optional Features > .NET Framework 3.5
  4. 4Install .NET 6/7/8 runtime from https://dotnet.microsoft.com/download
  5. 5Repair .NET: use the .NET Framework Repair Tool from Microsoft (for Framework 4.x)
  6. 6Install latest Visual C++ Redistributable (x86 and x64) from Microsoft

Tags

dotnetclrclr20r3net-frameworkruntime-error

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Frequently Asked Questions

Check the application's documentation, readme, or system requirements. You can also check Event Viewer for the CLR version in the crash event. Right-clicking the .exe > Properties > Details may show the .NET version.