Steps to reproduce:

Three ways to reproduce

First:

1. Create an empty project

2. Close the project and open the Unity Hub and Pass the command line arguments -activeBuildProfile Assets/Settings/BuildProfiles/Mac.asset (Or the windows asset for win users) and -readonly to the project

3. Launch the project and observe the crash

Second:

1. Create an empty project and install the latest mppm 1.3.0 pre-3 and at least unity 6000.0.20f1

2. Go to File- Build Profiles and switch the main editor to any of the build profiles (not the platforms, see photo for example)

3. Once done open Window- Multiplayer - Multiplayer Playmode and launch a virtual player by checking the checkbox next to one of the players

4. Observe to virtual player crashes

Third (2024.10.10):

1. Create a new project with Universal 3D template

2. In Project Settings -> Editor enable Parallel Import

3. Open File -> Build Profiles

4. Select Android/iOS platform and Add Build Profile

5. Switch to the new profile

Actual results: 

Crash occurs
(2024.10.10): Unexpected transport error from import worker 247. code=2 error=End of file error spam and asset importer crashes (the editor itself does not crash)

Expected results: 

No crash occurs and editor launches with desired build profile + mppm clone editors do not crash when the main editor is set to one of the build profiles
Reproducible with versions: 

6000.0.20f1 

Not reproducible with versions: 

6000.0.19f1

Tested on (OS): 

Mac 

Windows (On Windows, you might not get errors immediately, but if you restart the project it gets stuck in the loading screen and the project fails to open due to asset importer crashes as well)

Notes:

(2024.10.10) If the project gets into a state where it cannot finish importing the project, the asset importers keep crashing non-stop and adding new crash events. The next time you successfully open a project, all those crash events are sent.