Keep getting "Couldn’t migrate package ... because the asset save failed" error when migrating assets

Hello all, when I am trying to migrate my character blueprint or my animation blueprints I keep getting this error “Couldn’t migrate package (/Game/ThirdPerson/Input/IMC_Default) because the asset save failed. Destination File (C:/Users/me/Documents/Unreal Projects/CastleProject/Content/ThirdPerson/Input/IMC_Default.uasset)”. At first it used to say that the destination file was read only, but after changing the properties of the folder for my projects it just now says asset save failed. This migration error for some reason doesn’t properly migrate my variables for my character blueprint, and does not migrate my animation blueprint at all.

I’ve tried migrating to a clean project and I get the same error, and I’ve also migrated the entire project and that also didn’t fix anything. Both projects have the same plugins and are the same version of Unreal. I’ve migrated static meshes fine, and from the tutorials I’ve been trying I was able to migrate those assets, but not the character blueprint or animation blueprint I created. I’m not really sure where to go from here, since in the future if I want to migrate my assets then I’m just going to run into this problem again.

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Is the destination project closed? ( ie not open in the editor )

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I do have both projects open if that is what you are asking.

Try not having the destination project open…

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That seemed to help a little as now my animation blueprint actually has the blend space I created and the error no longer shows up, but I’m still running into the issue that all of the variables for the blueprints are gone.

Did you try it to a new ( closed ) project?

Also worth noting, is you cannot migrate to earlier versions of the engine.

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Not yet, I just created a new project so I can try that out.

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Ok so I still have it where the variables are gone, but there is another error that occurs when I do click on the migrated blueprint. It says that “Blueprint could not be loaded because it derives from an invalid class. Check to make sure the parent class for this blueprint hasn’t been removed!”.

It sounds like you’ve got some broken assets in the source project.

If you’ve ever moved or deleted things from windows, rather from inside the content browser, that could be the result.

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Hmm that may be possible, I am having some difficulty remembering so I’ll try to recreate the blueprint in another project and see what happens from there. Thanks for the help so far!

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Everything’s dependency is mapped out in the asset browser. If you move things without the engine knowing, it will lead to this kind of error.

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That maybe what happened since I just migrated another blueprint and I see all of my variables there.

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I do have a question about this. I made my project a C++ project even though I haven’t written anything for the project in C++ hoping for later to learn how to use C++ in unreal. Now the character blueprint shows that the parent class is “practice game character” and since I’m migrating to another project which also is a C++ project would this also be a reason for that error arising about the blueprint not being able to load due to an invalid parent class?

I created a new project and recreated the character and animation blueprint and then tried to migrate those blueprints to another new project but I still get this error “Blueprint could not be loaded because it derives from an invalid class. Check to make sure the parent class for this blueprint hasn’t been removed! Do you want to continue (it can crash the editor)?” for the character blueprint. If I click “Yes” after this error shows up, the blueprint opens and now none of the nodes are visible and I’m left with a blank screen when on the event graph.

Bizarre…

You should be able to migrate between similar project types and engine versions.

Maybe check this

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Not entirely sure how to add the breakpoints, but I tried again this time making the character and animation blueprints in a blueprint only project and then migrated to another Blueprint and C++ project where this time it worked. For some reason migrating from a C++ to another C++ project doesn’t work. For now I might just stick with the blueprint project until I decide to start learning on how to write C++ for games. Thanks for the help!

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