Apps · Drive, safety and recovery
What happens to my moved apps when the external drive is disconnected?
Short answer: Moved apps won't open until you reconnect the drive; nothing breaks and they work again once it's back. Keep apps you need on the go on your Mac.
They won't open until you reconnect the drive, because the app itself lives there. Everything else on your Mac works normally, and as soon as you plug the drive back in the apps open again — nothing needs repairing.
If you often work away from the drive, keep the apps you need on the go on your built-in drive, or move them back before you travel. Offloaded apps likewise need the drive to be restored.