--- title: "Choosing an external drive" url: https://storagestudio.us/wiki/choosing-an-external-drive category: "External drives" tags: ["external drive", "free up space", "data parking"] summary: "Storage Studio works best with a fast external SSD connected directly to your Mac and formatted as APFS. It checks any drive you pick — its format, its connection and, if you run the speed test, its read and write speed." updated: 2026-10-01T05:34:19.000Z --- # Choosing an external drive Storage Studio works best with a fast external SSD connected directly to your Mac and formatted as APFS. It checks any drive you pick — its format, its connection and, if you run the speed test, its read and write speed. Storage Studio moves folders and apps to an **external drive** and leaves shortcuts behind, so you'll be opening those files from the drive every day. The drive's speed and reliability become part of your Mac's. A fast solid-state drive (an SSD, including NVMe drives in an enclosure) connected directly to your Mac is the best fit. ## What Storage Studio checks When you pick a drive in **Choose External Drive** (see [Setting up your drive](https://storagestudio.us/wiki/setting-up-your-drive)), Storage Studio checks: - **It's external.** Your Mac's own disk can't be chosen — the whole point is to move things off it. - **It's local.** Network drives are refused. - **Its format.** APFS and Mac OS Extended pass; exFAT is allowed with a warning; FAT32 is refused. See [Drive formats](https://storagestudio.us/wiki/drive-formats). - **Its speed, if you ask.** **Run benchmark** writes a 128 MB test file to the drive, reads it back and deletes it, which takes about 5–10 seconds. ## Speed The speed test sorts drives into three groups: | Result | Read speed | Write speed | | --- | --- | --- | | Speed: looks good | 120 MB/s or more | 80 MB/s or more | | Speed: usable with warnings | below 120 MB/s | below 80 MB/s | | Speed: not suitable | below 40 MB/s | below 25 MB/s | If either speed falls into a lower row, the drive gets that result. A drive in the middle row works, but relocated folders and moved apps open more slowly, and long copies take longer. If you use a slower drive, such as a spinning hard disk, set **Parallel transfers** in Data Parking's settings to 1 or 2. ## Connection - The drive's details show its connection type as **Protocol**, for example USB or Thunderbolt. - **Leave it connected while you work.** Moved apps and relocated folders can't be opened while it's unplugged — see [When your drive is disconnected](https://storagestudio.us/wiki/when-your-drive-is-disconnected). ## Capacity Choose a drive with plenty of room for what you plan to move, plus space to grow. If you later want to switch to a bigger drive, **Transfer to a New Drive** needs the new drive to have at least as much free space as everything Storage Studio keeps on the current one, with a small margin — see [Switching to a new drive](https://storagestudio.us/wiki/transfer-drive-and-backup-drive). Storage Studio uses one external drive at a time for moving folders and apps. ```mermaid %% caption: How Storage Studio judges a drive you pick flowchart TD A[Pick a drive] --> B{External and local?} B -->|No| X[Not suitable] B -->|Yes| C{Format} C -->|APFS or Mac OS Extended| D[Compatibility looks good] C -->|exFAT| E[Usable with warnings] C -->|FAT32| X D --> F[Optional speed test] E --> F F --> G{Fast enough?} G -->|Yes| H[Use This Drive] G -->|Slow| I[Usable, but expect slower apps and copies] ``` *Flowchart — How Storage Studio judges a drive you pick. Outline:* - Pick a drive - leads to External and local? - External and local? - No: leads to Not suitable - Yes: leads to Format - Format - APFS or Mac OS Extended: leads to Compatibility looks good - exFAT: leads to Usable with warnings - FAT32: leads to Not suitable - Compatibility looks good - leads to Optional speed test - Usable with warnings - leads to Optional speed test - Optional speed test - leads to Fast enough? - Fast enough? - Yes: leads to Use This Drive - Slow: leads to Usable, but expect slower apps and copies See also: [External drive](https://storagestudio.us/wiki/glossary-external-drive), [Checking your drive's health and setup](https://storagestudio.us/wiki/checking-your-drive), [What to know about exFAT drives](https://storagestudio.us/wiki/exfat-drives). - **How do I move apps to an external drive on a Mac and still launch them?** Dragging an app to another drive can break it, because macOS expects it in /Applications. Storage Studio relocates the app to your external drive and leaves a shortcut in place, so it still launches normally from Launchpad, Spotlight, and the Dock — and you can move it back in one click. (https://storagestudio.us/faq) - **How do I use an external SSD as extra storage on a MacBook?** Plug in a USB-C or Thunderbolt SSD and let Storage Studio pair it with your internal drive as one workspace. It moves big folders, libraries, and apps to the SSD with a shortcut left behind, so your MacBook behaves like it has a much bigger disk — fast enough to work directly off the external drive. (https://storagestudio.us/faq) - **Can I move my Photos or Final Cut library to an external drive?** Yes — large Photos, Final Cut, and iMovie libraries are common space hogs. Storage Studio relocates them to an external drive while keeping them usable, leaving a shortcut so your apps still find them. Moving a folder to your fast drive keeps its files' modified and created dates, permissions,… (https://storagestudio.us/faq) - **Will moving files to another drive break my apps or Spotlight?** Not the way Storage Studio does it. It leaves a shortcut (symlink) at the original location, so apps, Finder, and Spotlight resolve everything as if it never moved — and the move is fully reversible. (https://storagestudio.us/faq) ## What links here - [APFS](https://storagestudio.us/wiki/glossary-apfs) - [Checking your drive's health and setup](https://storagestudio.us/wiki/checking-your-drive) - [Drive formats: APFS, Mac OS Extended and exFAT](https://storagestudio.us/wiki/drive-formats) - [External drive](https://storagestudio.us/wiki/glossary-external-drive) - [Setting up your drive](https://storagestudio.us/wiki/setting-up-your-drive) - [Switching to a new drive: Transfer Drive and Backup Drive](https://storagestudio.us/wiki/transfer-drive-and-backup-drive) - [The Setup Wizard](https://storagestudio.us/wiki/the-setup-wizard) - [Where a backup can go](https://storagestudio.us/wiki/backup-destinations) - [Where to start: pick your goal](https://storagestudio.us/wiki/where-to-start)