Description

Copied from Visual Studio feedback item Fatal error encountered when debugging .net 10 app using collectible assemblies in VS2026

Reproduction Steps

The error occurs with the app targeting .net 10 with the rc1 or rc2 Sdk (I’ve only tried these two). It does not occur when targeting .net 9. The program appears to complete correctly when not running under the debugger. I am using Visual Studio 2026 Insiders version 11111.16

A reproducible sample project is attached.
UnloadableTest.zip

Expected behavior

Debugging should succeed

Actual behavior

When loading and unloading an Assembly multiple times in new AssemblyLoadContexts Visual Studio will abruptly end debugging before program completion with a message box saying:

A fatal error has occurred and debugging needs to be terminated. For more details, please see the Microsoft Help and Support web site. HRESULT=0x80131c36. ErrorCode=0x0.

Regression?

Yes - from .NET 9

Known Workarounds

No known workarounds

Configuration

No response

Other information

No response