I found that if you try to migrate to a folder that already exists, it will cancel the migration. This can be very frustrating if the process is extremely slow, as you might spend 20 minutes waiting for the migration to get to the next step only for it to exit out. What would be nice is if there was an option to let you re-enter the folder name so it doesn’t derail your migration
Migration should always target the content folder, so it doesn’t make sense to pop up the folder selection again.
If you don’t select the content folder some references between migrated files might break.
If the destination project is closed you shouldn’t have problems migrating (even if the folder already exists), this usually happens when you have both editors opened and one is preventing the other from overwriting files