External drives · Mounting and drive problems
Why does my external drive take a long time to appear after I plug it in?
Short answer: A hard disk needs to spin up, and after an improper eject macOS checks the drive before mounting it, which can take a while on big drives. Let the check finish, eject properly next time, and run First Aid if it's slow every time.
A short delay is normal — a hard disk has to spin up and macOS reads the drive before showing it. A long delay usually means macOS is checking the drive first, which it does after the drive was last disconnected without ejecting, or when it suspects errors.
What helps:
- Let the check finish; unplugging again restarts it.
- Eject properly next time so the check isn't needed.
- If it's slow every time, run First Aid in Disk Utility and try another cable and port.
- A large hard disk that's slow on every connect and getting slower can be a sign it's wearing out — keep a copy of what's on it.
Storage Studio notices the drive once macOS has mounted it; see how quickly it notices.