Opening blueprint or struct crashes engine after 4.12 upgrade

I converted my 4.11 project to 4.12. First, my project would crash whenever I tried to open it so I changed the default editor level in the .ini file to another empty one and it worked fine.

BUT

Now, trying to open pretty much any struct, blueprint or level I made crashes the whole engine.

What’s about that ?

Hello kurosu143,

I have a few questions for you that will help narrow down what issue it is that you are experiencing.

Quick questions:

  1. Can you reproduce this issue in a clean project?
  2. If so, could you provide a detailed list of steps to reproduce this issue on our end?
  3. Could you provide screen shots of any widgets involved with this issue?
  4. Could you provide the complete callstack that is given after the crash?
  5. Could you try deleting the saved and intermediate folders before upgrading the project and let me know if this helps?

Hello kurosu143,

We have not heard back from you in a few days, so we are marking this post as Resolved for tracking purposes. If you are still experiencing the issue you reported, please respond to this message with additional information and we will offer further assistance.

Thank you.

Hello Rudy, unfortunately, my main hard drive happened to die the day after I posted about my issue so I wasn’t able to respond.
I have tested things now and I’m still having the same issue.

  1. I can’t reproduce the issue in a clean project.

  2. I’m not sure what you mean by that. I can’t really provide any screenshot since it crashes whenever I try to open any blueprint asset.
  3. I put the crash log on google drive, if that’s what you mean : https://drive.google.com/file/d/0B4IJAgzEf7KGQm5xdWNpR0NPUmM/view?usp=sharing
  4. I use a clone of the project to try and upgrade it and that already deletes the saved and intermediate folders.

From reading the crash log, it seems UE might try to compile children before their parent, could that be caused by me when I renamed blueprints ?
I noticed UE is having problems with renamed blueprints so that might be the issue.

Anyway, looking forward to your reply.

EDIT :
Upon further investigation, opening the project and opening up my NPCShop blueprint (first blueprint with fatal errors in the crash log) seems to fix the crashing issue ; I can open everything fine after that. BUT I have to do this every time I open UE and it takes a few minutes to just open up the NPCShop blueprint. Every blueprint I open after this one opens up instantaneously. It’s like something is compiling whenever I open the NPCShop blueprint.

EDIT 2 :
Upon further further investigation, I had renamed and moved my NPCShop blueprint at one point and did not delete the old folders and uasset files UE keeps in. I deleted them in explorer and it pretty much fixed everything, although I had to relink all references to the NPCShop blueprint since they were still referencing the old blueprint somehow. So yeah, the crashes were caused by bad references to non-existant blueprints.

im havng a constant crash issue almost every time since engine updated to 4.12.4

Hello Guiboune,

I am happy to hear that you were able to find a solution to your issue. I will be converting your last comment to an answer. If this issue arises again please feel free to reopen this thread with additional information and we will assist you further.

Make it a great day

For anyone having the issue, it’s fixable by moving the struct in a different folder.