My Mac HFS drive suddenly won’t mount after a restart, and I’m worried about losing important files. I haven’t tried repairs yet because I don’t want to make the damage worse. What’s the safest first step for HFS data recovery, and should I clone the drive before using any recovery software?
If you lost files from an HFS or HFS+ drive, the main thing is to avoid making the situation worse. Deleted files, an emptied Trash, a quick format, or a weird macOS issue does not always mean the data is gone for good. A lot depends on what happens next.
Stop using the drive
This is the part people skip, and it matters.
When macOS deletes a file, it usually removes the file’s record from the file system. The actual data may still be sitting on the drive until something new overwrites that space. So the more you use the drive, the worse your odds get.
If it’s an external drive, disconnect it for now. If it’s your Mac’s internal drive, don’t download recovery tools, install apps, or copy new files onto it unless you have no other option.
Do a quick check first
Open Disk Utility and see whether the drive shows up with the right size. If it does, that’s usually a decent sign.
For an external drive, also try a different USB cable or port before assuming the drive itself is damaged. Sometimes it really is just a bad cable.
If the drive supports SMART status, check that too. If SMART looks fine, you can usually move on to file recovery. If the drive has read errors, bad sectors, random disconnects, or keeps hanging, it’s safer to make a disk image first and scan the image instead of hammering the original drive over and over.
Try recovering the files before repairing the drive
Unless you already have a Time Machine backup, I’d usually try recovery software before running repair tools. Repairs can change the file system, and that is not always what you want when the goal is getting deleted files back.
Disk Drill is a common pick for this because it handles HFS and HFS+ well, and it can often see drives that Finder refuses to mount. It’s also straightforward enough if you have not done file recovery before.
The basic process is simple:
- Install Disk Drill somewhere other than the drive you’re trying to recover from.
- Open it and choose the HFS or HFS+ drive.
- Click Search for Lost Data.
- Use the Universal scan for most normal recovery cases.
- Let the scan finish if you can. You can browse results while it runs, but waiting usually gives you a fuller list.
- Preview the files you care about. If a file previews properly, that’s a good sign.
- Select what you want and click Recover.
- Save the recovered files to a different drive, not the original one.
The preview feature is worth using. It helps you confirm that photos, videos, documents, and other files are actually recoverable before you spend time saving a bunch of broken results.
If the Trash was emptied or the drive was formatted
That still does not automatically mean everything is gone.
An emptied Trash or quick format usually removes file system references before it removes the underlying data. If the space has not been overwritten yet, recovery software may still be able to find the files. That’s why stopping immediately gives you the best shot.
When to quit DIY recovery
Software recovery is meant for deleted files, quick formats, and file system problems. A physically failing drive is a different situation.
I’d stop scanning the drive yourself if you notice any of this:
- clicking, grinding, or other strange sounds
- the drive no longer appears in Disk Utility
- constant disconnects
- scans freezing or ending with read errors every time
At that point, repeatedly powering it on can make the damage worse. If the files are important, a professional recovery lab is the safer route.
Hopefully it’s just accidental deletion or logical file system damage. Those are the cases where recovery software usually has the best chance, especially if you act before new data gets written to the drive.
A failed mount can get worse just from being repeatedly poked by macOS, especially if the drive is starting to time out. I’d leave First Aid alone for now and make the first real step a clone or disk image to another drive, assuming Disk Utility can still see the HFS volume or the physical disk. After that, scan the copy with whatever recovery tool you trust, Disk Drill included, and save recovered files somewhere else. If the drive is clicking, disappearing, or imaging crawls with read errors, stop there rather than forcing more scans.
Do not click Initialize, Erase, or First Aid just because Disk Utility offers it. That prompt only means macOS can’t make sense of the file system right now, not that you should “set it up” again. Initializing the disk is exactly the kind of thing that can make recovery messier.
I agree with the clone-first advice, but the detail I’d watch is what you clone. If Disk Utility shows the physical drive but the HFS volume is missing or grayed out, image the whole device, not just the broken volume. A lot of recovery attempts go sideways because people only copy the visible partition and leave behind the damaged partition map or catalog info that recovery tools might still use. Use a separate destination drive with plenty of space, and don’t save anything back to the problem disk.
After you have an image, then scan the image with Disk Drill or another recovery app. That way the original drive gets touched as little as possible. Be prepared for the recovered folder names to be ugly if the HFS catalog is damaged, even when the actual files are still recoverable. If the drive vanishes during imaging, makes noise, or the copy speed drops to nothing for long stretches, stop treating it like a software problem. At that point the safest “first step” is really powering it down and deciding whether the files are worth a lab.
If it’s only HFS directory damage, a clone gives recovery tools something safe to work on; if the drive is physically failing, every mount attempt is another little gamble. I’d shut it down, connect it to another Mac only long enough to make a raw image/clone, and avoid letting macOS auto-repair, index, or “initialize” anything before that.