Migration damages blueprints

Trying to migrate my code to a new project. Blueprints which are fine in the original come in with missing nodes and tons of errors. I have some c++ code that has an enum in it, the migration doesn’t find it even though the c++ was already hand copied to the new project. Looks like I’ll just have to fix all the errors one by one.

I have a c++ actor which some blueprints inherited from. The migration fails to find that code and now I can’t even open and fix that blueprint. It’s damaged and can’t open the editor.

Hi sgehrman,

I just wanted to get a better idea of what you are migrating, and how. Are you moving assets (static meshes, Blueprints, etc) from one project to another project where both projects are using the same Engine version? If so, are you using the migrate feature in the Engine to do so? When you copy the code, are you copying the code from one file and pasting it into another, or did you copy the entire file over?

When you migrate a Blueprint that is based on a custom code class to a different project, it won’t work in the new project because it is looking for the custom class in the old project, which it no longer has any access to. When it can’t find the parent class that it is looking for, it resets its parent to None and you can no longer open that Blueprint. Unfortunately in this case, bringing the code class into the new project as well doesn’t help. There is already an existing ticket in place to address this (UE-2390).

Hi sgehrman,

We have not heard back from you for a few days. Do you still need help with this issue? I will be marking this post as resolved for internal tracking purposes, but please feel free to add a comment to re-open the post at any time if you need any more help.

Still having constant problems of nodes being disconnected, files being corrupted and constant problems. If I refactor my code, change names of entries in structures, rename functions, move or copy files, I always get corruption and problem and broken nodes. This is after spending a week migrating my code to a new project and getting out all the corruption. Basic stuff in the editor is completely broken.

Hi sgehrman,

Sorry for the delay. Are you trying to upgrade a project from a previous version of the Engine to 4.8.3? Can you provide a specific example of a change you made that resulted in a corrupted Blueprint or broken nodes? Would it be possible to get your original project to test with?