---
id: moving-folders.what-should-i-not-move-to-an-external-drive
url: https://storagestudio.us/faq/moving-folders/what-should-i-not-move-to-an-external-drive
category: "Moving folders"
subcategory: "How moving folders works"
question: "What should I not move to an external drive?"
alt_questions:
  - "Which folders should stay on my Mac?"
  - "What is unsafe to relocate?"
  - "Can moving the wrong folder break my Mac?"
  - "folders you should never move off the startup disk"
  - "What shouldn't I put on the fast drive?"
short_answer: "Keep on your Mac anything you need with the drive unplugged, folders an app is still writing to, browser profiles and app data holding sign-ins, and macOS system folders. What's Using Space only offers a move where it's safe."
tags: ["moving folders", "safety", "what to move"]
related: ["https://storagestudio.us/faq/moving-folders/which-folders-are-worth-moving-to-an-external-drive", "https://storagestudio.us/faq/moving-folders/why-wont-storage-studio-move-my-browser-folder", "https://storagestudio.us/faq/moving-folders/why-was-my-move-blocked-for-recent-writes"]
applies_to: "all"
last_reviewed: 2026-10-01
---

# What should I not move to an external drive?

Keep anything you need when the drive is unplugged, anything an app is writing to right now, and folders that hold an app's sign-ins and settings. Moved files are only reachable while the drive is connected.

In practice that means:

- **Work you need on the go** if you often travel without the drive.
- **Folders in active use** — a project mid-build or a folder a sync app is still writing to. Storage Studio checks for recent writes and holds the move.
- **Browser profiles and app data with sign-ins** — Storage Studio leaves these alone because moving them would sign you out and break when the drive is away.
- **macOS system folders** — Storage Studio doesn't offer to move them.

When in doubt, use **What's Using Space**: it only offers **Move to fast drive** on folders it can move safely.

See [what happens when the drive is unplugged](https://storagestudio.us/faq/external-drives/)