Bug Report: Unity Editor Freezes with “Reloading Domain” Status During Debugging with JetBrains Rider

Environment

• JetBrains Rider: Version 2024.2.5
• Unity: Version 6000.0.32f1

Summary
When debugging a Unity project using JetBrains Rider, the Unity Editor consistently freezes with a “Reloading Domain” status after a few debugging iterations. This issue disrupts the typical debugging workflow, persists across application restarts, and requires a temporary workaround that is only effective for a limited number of debugging cycles.
Steps to Reproduce

1. Open a Unity project in JetBrains Rider.
2. In Rider, click “Attach to Unity Editor & Play” to initiate a debugging session.
3. When a breakpoint is hit in Rider, stop the debugging session.
4. Verify that the Unity Editor exits play mode as expected.
5. Add additional breakpoints in the code, positioned before the previously hit breakpoint (as part of a standard debugging process).
6. Repeat step 2 by clicking “Attach to Unity Editor & Play” again.
7. Perform this debugging loop multiple times (e.g., 1-2 iterations).

Expected Behavior
The Unity Editor should seamlessly handle multiple debugging sessions without freezing.

The “Reloading Domain” process should complete quickly, allowing uninterrupted development and debugging.

Observed Behavior

• The debugging process functions correctly for the first 1-2 iterations.
• After a few cycles, the Unity Editor freezes indefinitely with a “Reloading Domain” status (tested for up to 10 minutes without resolution).
• Closing and reopening both Rider and the Unity Editor does not resolve the issue:
  • Upon reopening the Unity Editor first and launching Rider (e.g., by double-clicking a script), the freeze occurs immediately on the first attempt to debug with “Attach to Unity Editor & Play”.
  • Even without Rider attached, the Unity Editor independently becomes stuck in “Reloading Domain” when entering play mode.
• Repeatedly closing and reopening both applications fails to restore normal functionality.

Workaround

• In the frozen Unity Editor, select File > Save Project, then close the editor.
• Reopen both the Unity Editor and Rider.
• Debugging resumes working for 1-2 additional sessions before the freeze reoccurs.

Impact

• This issue results in significant productivity loss due to frequent freezes and the need to repeatedly apply the workaround.
• It severely disrupts the debugging workflow, hindering efficient code iteration and testing.

Additional Notes

• This behavior appears specific to the combination of JetBrains Rider and Unity, as similar workflows using other IDEs (e.g., VSCode for backend development) do not exhibit this issue.
• The persistence of the freeze across application restarts suggests a deeper underlying problem in the integration between Rider and Unity.

Request
Please investigate and address this issue to ensure a stable and reliable debugging experience for developers using JetBrains Rider with Unity. The current behavior significantly impacts development efficiency, and a permanent fix would greatly benefit the community.