My external hard drive suddenly stopped showing up on my Mac, but it contains important files I need to recover. It isn’t appearing in Finder, and I’m looking for safe troubleshooting or data recovery options that won’t erase the drive.
Repeated repair attempts can make recovery harder if the drive is physically failing, so don’t initialize it, erase it, reformat it, or copy anything onto it. If macOS offers to “fix” an unreadable disk, cancel that prompt for now.
Start with the non-destructive checks: try a different cable, port, and power adapter if the drive uses one. Avoid USB hubs. In Finder Settings, confirm “External disks” is enabled under both General and Sidebar. Then open Disk Utility and choose View > Show All Devices. You can also check System Information under USB or Thunderbolt to see whether the Mac detects the hardware at all.
If the physical drive appears in Disk Utility but its volume is gray, try Mount once. I’d avoid running First Aid when the files are irreplaceable because it changes filesystem structures. A safer route is to create a byte-for-byte image or clone first, then work from that copy. Recovery software such as Disk Drill for Mac may help when the drive is detected but won’t mount. Save recovered files to a different drive, never back onto the problem disk.
If the drive does not appear in Disk Utility or System Information, recovery software usually cannot access it. Test it on another computer to rule out the Mac, but stop if it clicks, spins up and down repeatedly, disconnects, or becomes unusually hot. Those symptoms point toward hardware trouble, where a professional recovery lab is safer than repeated power cycles. For very important files, that is the point where DIY attempts can cost more than they save.
2 Likes
The enclosure’s USB bridge may have failed even if the actual disk is fine. If it’s a standard removable SATA drive, testing it in a compatible enclosure or dock can restore access, but don’t open sealed, RAID, or warranty-covered units.
Don’t initialize, erase, or run First Aid on the drive before recovering the files. Check whether Disk Utility can see the physical disk; if it does, create an image or scan it with Disk Drill, saving recovered files to a different drive.
The imaging advice everyone keeps repeating has a catch nobody mentioned: a plain byte-for-byte clone reads the disk start to finish, so on a drive that’s already struggling it spends the most time hammering the exact bad areas that can push it over the edge. If the drive is even a little flaky, you want a tool that grabs the healthy regions first and comes back for the damaged spots later. That’s the difference between a normal clone and a proper rescue image. Disk Drill can build an image and it’s fine when the drive is basically healthy but just won’t mount, which matches what @datahub778 said. For a disk that stutters or drops off, I’d reach for something built around ddrescue instead, since it handles read errors more gracefully.
Before any of that, pull the SMART status if the drive shows up in System Information or Disk Utility at all. Reallocated sectors climbing or a ‘failing’ flag tells you immediately whether you’re dealing with a dying disk or just a cranky enclosure. @neonarchitect3877zon is right that the USB bridge fails more often than people expect, and swapping the bare drive into a dock is one of the cheapest tests you can run. Just don’t do it with anything hardware-encrypted or a sealed portable unit, because those often tie the encryption to the original board and you’ll lock yourself out.
One thing worth checking that’s easy to miss: Mac sleep and USB power settings. Some external drives spin down and refuse to reappear until a full shutdown, not just a restart. Fully power off the Mac, unplug the drive, wait a minute, then boot and connect it directly.
Honest expectation setting though. If it’s clicking or cycling power, imaging software of any kind is the wrong move, and every attempt costs you. That’s lab territory, and the bill scales with how many times it got power-cycled first.