I’ve got the exact same error when trying to migrate assets from a project that was built in the latest version of Unreal 5. Both projects are just Blueprint projects. Any other things to try?
The full error message I got when trying to migrate was:
Some selected assets don’t have a corresponding content root in the destination.
/HairStrands
/ControlRig
/Niagara
Would you like to migrate all selected assets into a folder with consolidated references? Without migrating into a folder the assets in the above roots will not be migrated.
The migration process has just dumped everything in the content folder.