External media
Recovering files from external media on a Mac
A camera SD card wiped by mistake, a USB stick reformatted too quickly, an external hard drive that macOS suddenly says it can't read: these are the situations where data recovery works best. Unlike the internal SSD of a recent Mac, these devices are usually neither encrypted by default nor cleaned up by TRIM. Deleted files stay physically present as long as nothing has been written over them.
So it all comes down to what you do first. This guide explains why you must stop writing to the device, how a scan works, why you always restore to a different disk, and when to give up on software and call a lab.
Why recovery works on these devices
On a file system such as exFAT, FAT32 or HFS+, deleting a file doesn't erase it: the system simply removes its entry from the index and marks its space as available. The bytes stay where they are. A quick format does the same thing for the whole disk: it creates a new, empty index without touching the data.
A recovery tool can then work in two ways:
- Reading what's left of the index: entries marked as deleted often give the name, size and original folder.
- Searching for signatures: by going through the device sector by sector, the tool recognizes the start of a JPEG, a RAW file, a MOV video or a PDF. Names are lost, but the content is often intact.
Anything written after the deletion (new photos, copied files, installing software) can cover those bytes for good.
Stop writing to the device: rule number one
- Take the card out of the camera or drone. Don't shoot another photo on it: the camera would write precisely into the freed space.
- Eject the device properly from the Finder (eject button in the sidebar).
- Decline initialization if macOS shows “The disk you attached was not readable by this computer”: click Ignore or Eject, never Initialize.
- Lock the SD card as read-only with its small side switch, if it has one.
- Don't run First Aid in Disk Utility before you've recovered what matters: the repair rewrites structures on the disk.
Your chances by device
| Device | Common format | Chances | Note |
|---|---|---|---|
| SD, microSD, CFexpress card | exFAT, FAT32 | Good | If the camera hasn't recorded over it |
| USB flash drive | exFAT, FAT32 | Good | A quick format is usually recoverable |
| External spinning hard drive | HFS+, exFAT | Good | Unless there's a mechanical failure |
| External SSD | APFS, exFAT | Low to fair | An SSD that supports TRIM erases quickly |
| Encrypted APFS volume | Encrypted APFS | None without the password | With the password, like a normal disk |
| iPhone, Android | MTP, PTP access | Accessible files only | No low-level scan possible |
A full format (the security option in Disk Utility, or a “low-level” format in a camera) writes over the entire surface: in that case, nothing can be recovered.
How a scan works with MacNeat
MacNeat's External Media Recovery module is designed around these rules:
- Connect the device (card reader, USB port, camera in storage mode). It appears in the list of devices, with its format and capacity.
- Start the scan: MacNeat reads the device without writing to it. It lists the current content on one side, and on the other the deleted files that can still be recovered, with a preview when possible (photos, videos, documents).
- Choose the files to recover, filtered by type or date.
- Pick a destination: MacNeat requires a different disk than the source, such as your Mac or a second external drive. Restoring to the scanned device is impossible.
For a camera connected over USB, access depends on the mode the camera offers. The most reliable option is still to read the card directly with a card reader.
Why you always restore to a different disk
Restoring a file means writing it. If you write it to the original device, the file system will pick free space, which is exactly where the other deleted files are sleeping. Every file restored to the wrong place can destroy another one you haven't recovered yet, or corrupt the one you're restoring.
So before you start, plan a destination with enough free space (at least the size of the files to recover, ideally the capacity of the device). Then check the restored files by opening them before you reformat or reuse the original device.
The honest limits
- The Mac's internal SSD: this module doesn't apply to the internal SSD of a T2 or Apple silicon Mac. With TRIM and hardware encryption, a file emptied from the Trash can't be recovered there (see Mac data recovery).
- Encrypted APFS volume: without the password, nothing is readable. With the password, unlock the volume in the Finder first.
- Phones: a connected iPhone or Android phone only exposes its accessible files (photos and videos in DCIM, for example). MacNeat reads and copies them, but can't scan their memory in depth for deleted files. On iPhone, check the Recently Deleted album in Photos instead.
- Partially overwritten files: a photo may come back half gray, a video may not play. That means some of its data was overwritten.
Clicking or unrecognized drive: call a lab
If an external hard drive clicks, grinds or beeps, spins up and then stops, or if Disk Utility no longer sees it at all, the problem is hardware. No software, MacNeat included, can fix it, and every attempt can make the platters worse.
Unplug the drive, don't shake it, don't put it in the freezer (an old myth that causes condensation) and contact a data recovery lab. The same goes for a bent or broken SD card, or a USB stick that gets hot without being recognized: techniques for reading the memory chips directly exist, but only in a lab.
Prevent rather than recover
- Import your photos after every shoot and keep two copies (Mac and backup) before formatting the card in the camera.
- Format cards in the camera rather than on the Mac, and replace them after a few years of heavy use.
- Always eject a device before unplugging it.
- Turn on Time Machine (System Settings > General > Time Machine): MacNeat warns you if the last backup is too old (see Data Protection).