UE4 can't open project after updating to 4.10

I’m trying to update the project from 4.9.2 to 4.10, but loading of the updated project freezes each time at 73%. The process doesn’t use CPU time and doesn’t affect the disk. In my last attempt it continues for a more then 4 hours so, I guess, waiting is useless here. I also tried to recompile the project manually in VS2015 and launch as a debug instance, but with the same result.
By the way, another test projects open without any problems after update to 4.10 on my system.

log: log - Pastebin.com

UPD. It stucks on initializing phase even if i choose ‘skip conversation’ option when i try to launch the project in 4.10. Any ideas? I really need to upgrade to 4.10.

Hey YuriNK-

Are you using the Launcher version of the engine or are you using a source build? When upgrading the project did you do so from the project browser and select “Make a copy”? If you open the project directory and right click on the .uproject file and select Switch Engine Version are you able to open the project?

It’s a launcher engine version. I used both ‘make a copy’ and ‘skip conversation’.
And that’s definitly a some problem with a blueprint classes derived from c++ classes.

Today I finally loaded updated project after replacing my own GameMode class to basic class. Then I faced a permanent crashes when tried to move another blueprints derived from c++ classes from one folder to another. But it looks like now I can move it after project folder renaming (i made it to avoid external reference warnings).

By the way, attemt to use my old c-derived GameMode class still can block project loading.
So, to explain:

  1. I have, for example, MyCppGameMode class and derived blueprint bp_MyCppGameMode created in 4.9. If I use bp_MyCppGameMode, project loading stucks at 73%.

  2. If I set standart GameMode as a base class in class settings of the bp_MyCppGameMode blueprint, the project loads fine (but I have compile error, obviously).

  3. If I create new bp_MyCppGameMode410 derived from MyCppGameMode in UE 4.10 and use it, game works. But, obviously, I have another compile errors here.

So I createed a new blueprint class and copied functions, variables and nodes from the old class. It works.

I tried to follow your example by setting up a GameMode created in code with a blueprint based off of it set in the editor and then upgrading the project from 4.9.2 to 4.10. The project was able to open without issue after the conversion. It’s possible that the game mode (class or blueprint) became corrupted in the conversion process. I’m glad to hear that recreating the game mode solved the issue for you.

Cheers