Runs in editor, crashes compiler or when reloaded into editor

This is a more general followup to my earlier bug here:

I have a project that runs fine in the editor, but crashes if I try to cook it or compile it. It also crashes if I save the project and try to reopen it without disconnecting some of my transforms first.

What appears to be the basic problem are transforms in an anime BP where two or more transforms are applied to the same bone. For example, I have a basic “stand” animation (via layered blend per bone) that might be modified (by transform (modify) bone) before it gets fed into the final animation pose.

Looking at the documentation, I don’t see anything that would prohibit modifying the same bone more than once, and running it in the editor runs fine. But it seems to be a problem for the compiler.

Hi ,

Does this occur in a clean project with no additional content or is it limited to one project? Additionally, what version of the editor are you using?

Just my project, though I haven’t tried to reproduce it in a new project.
This happens with both 4.6.1 and 4.7 release 8.

Another odd thing – I can sometimes get it into a state where none of the anime BP transforms are applied (everyone stands in the T pose), and if I build an app they are still in the T pose, but if I recompile the anime BP (which shows that it doesn’t need to be recompiled) it will work in the editor. It still builds with everyone in T formation, though.

Hi ,

Can you provide the asset that crashes/regresses into a T-pose in a file. There are a number of things that can cause this if not set up properly in Animgraph, Eventgraph, etc.


To save space, I’m just zipping Config and Content folders. I’ve tested that these bugs also happen if you:

  1. Create a new 3rd person project from 4.7r8 (without the additional content)

  2. Empty out the other folders.

  3. Put these Config and Content folders in it.

More in the readme.txt in the

It’s still too big to attach (44 meg), so it’s up on here:

Click on “All Files: HTTPS” on the left and download the .

There’s something really strange going on – I finally tried making a new state machine, and all it does is play the regular walking animation into the final pose, and it runs fine in the editor, but closing and reopening, or packaging it and running the app has them all in T-pose again.

This isn’t doing ANY bone blending of any kind, just playing one animation straight up into the final pose.

I’m using an ascii .fbx file exported from blender.

After more experimenting, it seems like the animation gets disassociated, somehow, from the object. I’ve found that if I temporarily change the object from “use animation BP” to “use animation asset” and back it seems to fix the build and close/reopen problems.

Doesn’t seem to fix the crashes, though…

Going way way back in old versions, I’ve found one that doesn’t have the bug, but if I convert it from 4.6.1 to 4.7.1, it builds the app but the app crashes. I’ll try to see if I can get it to work under 4.7.1 since later versions seem to have the bug from then on.

After even more experimenting, it looks like my animation BP (parent is AnimInstance) and its children is somehow corrupted – I can’t change it into a simple animation that works, but if I make a brand new one, that works as expected.

This might not be a bug, strictly speaking, but more a bad/corrupted animation BP, though it might have been originally munged due to a bug.

After making a new animation BP and rejiggering everything, I can definitely say my old animation BP is somehow corrupted. Everything works as expected now.

It might be worth figuring out how it got corrupted (I didn’t do anything too strange), but this bug can be closed.

Hi ,

Thanks for the update. I loaded the files on my Mac and followed the instructions in the Read Me file but was only able to recreate the issue described. I agree that one of your original files has become corrupt. I suggest making a copy of the original project file that still works. Opening that file, then migrating the assets to a new 4.7.1 empty project.

If they perform properly there, then migrate the remaining assets from the copied folder.

Let me know if this resolves your issue.


I had already tried that – copying the whole project seems to copy the corruption. However, copying just the Anim BP and reconnecting the copy in place of the original finally worked.