Instead of
C:/Users/me/Documents/Unreal Projects/CastleProject
try copying it to for example
C:/Unreal Projects/CastleProject
then migrate the assets again and see if it still throws errors.
Instead of
C:/Users/me/Documents/Unreal Projects/CastleProject
try copying it to for example
C:/Unreal Projects/CastleProject
then migrate the assets again and see if it still throws errors.