How to use mix-mode debugger for Unity Mono process

We bring the mix-mode debugging feature starting from the Rider 2025.1.2 release.

You can debug both .NET and C/C++ code in a single session. The current implementation supports only the Mono Windows X64 scenario.

How to enable the beta feature (enabled by default from RIDER 2025.2 EAP 3)

1. In Rider, press Shfit + Shfit to open the Search Everywhere modal. Search Registry and open it. Or, in the Help | Find Acton, type in Registry.
2. Find the rider.debugger.enable.mono.mixed.mode flag, enable it.

3. In the Run/Debug Configuration on the top-right, tick "Use mixed mode debug" to enable it. 
   

   You can also enable mixed mode debugging for .NET Framework apps in .NET Project/.NET Executable run configurations. Please note that "Mono" should be selected in the "Runtime" dropdown

   

4. Start a debug session. It could be a bit slower on the first execution, since the debugger needs some time to load related symbols.

A sample workflow:

Screen Recording 2025-05-09 at 16.06.12.mp4

What are the differences when enable it?

If you refer to native libraries in your C# code, like using DllImport to declare interoperates, you can step into the native C/C++ code now.

Also, you can add breakpoints in C/C++ code. Debugger will navigate from the C# debug session to the native code.

Ensure you have loaded symbols of the target dll, you can check the symbol status in the "Modules(LLDB)" tab in the debugger.

How to view all frames

You may also find it useful to disable library frames filtering via "Rider Show/Hide Library Frames" action to see all the frames