Unable to open certain levels in projects migrated from Unreal Engine 4 to 5.

I migrate 4.22 → 4.27 → 5.03
Everything goes well on ue5…but unable to open the most important level.
Level has almost 2000 actors…It’s too hard to test…because for testing i have to migrate everytime…
anybody has similiar issues?

Hi there,
It is crashing when opening the project or playing in editor? It can be caused by many blueprints with compilation errors. If you migrate from 4.22 to 4.27, can you still open the level?

Also, have you tried to cook/package the project and check the output log?

there is no issue on 4.22 and 4.27…only 5 has problem.

In this case, can be compilation errors in many blueprints in UE5.
For instance, do you have vehicles in that level? It is potentially a problem, because the UE4 plugin for vehicle is deactivated by default in UE5. So, all blueprints will be invalid.

Here a few topics to search in your project:

  • If you have vehicles in your old project, before migrating to UE5, make sure to open your UE5 project, enable the PhysX Vehicles plugin and restart you project. Then you can migrate.
  • If your old project uses other plugins not available in UE5, similarly to the vehicles, all blueprints that call unavailable plugins will become invalid after migrating.
  • After migrating, if errors persist, try to package your game, enabling “cooking on the fly” and read through the output log. Invalid nodes will be highlighted as red messages (errors) or warnings (yellow).

Hope that helps.