Made the mistake of my life, in the blink of an eye, by formatting my internal hard disk drive to the AFPS format. It originally had a journalled format under High Sierra OS. I have not used it since. (I had two drives connected with similar names, and chose the wrong one to erase). I have no backup, so... Please tell me there is a way to unformat the drive?!
[Re-Titled by Moderator]
iMac 21.5″, macOS 13.5
" I have no backup, so... Please tell me there is a way to unformat the drive?!"
Oh boy, with no backup your user files (data, photos, email, music, videos, etc) are gone forever. There is NO recovery possible after formatting. The internal storage cannot be unformatted and anything that was on that internal storage cannot be recovered. All you can do is install macOS. Sad but true.
" I have no backup, so... Please tell me there is a way to unformat the drive?!"
Oh boy, with no backup your user files (data, photos, email, music, videos, etc) are gone forever. There is NO recovery possible after formatting. The internal storage cannot be unformatted and anything that was on that internal storage cannot be recovered. All you can do is install macOS. Sad but true.
MartinR wrote:
Actually, it may be possible to recover data from a drive that was accidentally reformatted. Prosoft Engineering Data Rescue 6 is one app that can attempt this.
Formatting does not normally erase data from the disk unless you choose one of the secure erase options, in which case all data is overwritten by 0's and 1's.
In normal (quick) formatting all that happens is the disk file system is replaced. (The method & structure by which data is stored & retrieved from the disk.) Doing that makes it appear that the disk is empty and the system will act as if the disk is empty. But unless the data was physically erased it remains on the disk and may be recoverable.
This is a bit iffy even with hard drives … but if the data is important, and there is no backup, it may be "better than a poke in the eye with a sharp stick" (one of the ratings an old Mac magazine used to give in reviews).
On SSDs, the chances of recovering data this way may be lower, due to the way that wear leveling often works.
If you're talking about the internal SSD of a Mac with a T2 security chip, or an Apple Silicon chip, that you erased using "Erase all contents and settings" in Monterey or later, forget it, unless you're the NSA or KGB. Maybe even then. Because even if you can get at the data that wasn't physically erased (hard with a SSD), all of that data will be encrypted with a key that the T2 chip or Apple Silicon chip has intentionally forgotten …
SOLVED. (more or less....)
The iMac in question was a mid-2011 model, the internal Hard Drive that was erased, was a mechanical SATA HD, running High Sierra. As one member pointed out, (perhaps) because I only erased the drive, and because I realized my error before going ahead with the full AFPS format, I was able to recover the files, with a data recovery program (I used "Disk Drill". Though I've read good things about "Data Recovery 6", also).
I haven't checked yet to see how well DD recovered all the files. Oddly, it says it recovered 1.5TB worth of files, when the drive was only 1TB! I did see the files have lost their names though, along with their original folders. With 300,000 files to rename, I have indeed lost the names. But better than, than losing the files!
Thanks to all who replied, for your kindly support. As it is often stressed, we all know the importance of having a "Time Machine" back up, at all times. And I did, for this drive... but, I had temporarily erased it, as I needed it for other backups.... :-(
To the need for an active backup drive, I would add... "use distinctly different names for all your drives!". :)
Actually, it may be possible to recover data from a drive that was accidentally reformatted. Prosoft Engineering Data Rescue 6 is one app that can attempt this.
Formatting does not normally erase data from the disk unless you choose one of the secure erase options, in which case all data is overwritten by 0's and 1's.
In normal (quick) formatting all that happens is the disk file system is replaced. (The method & structure by which data is stored & retrieved from the disk.) Doing that makes it appear that the disk is empty and the system will act as if the disk is empty. But unless the data was physically erased it remains on the disk and may be recoverable.
Yes, it does, and very nicely too. With each file type found listed as a different color icon, clearly showing how many files of each type. Now that I am in the actual process of recovering those files, I will revise my answer to say, that after doing a FULL scan of the erased drive (which only seems to come up once you do a partial scan), Disk Drive shows 851GB of recoverable files, on the 1TB drive. (Not 1.5TB, as initially reported). They are both user and system files - the whole shebang.
It looks like it will take about 6 hours to recover the files (and about the same amount of time to scan the hard disk drive). Moreover, I am really happy to see that my file structure appears to be intact! It is recreating not just the folder structure, but the original file names. And I have already checked some large (~400mb) video files it recovered, and they do work.
Of course, I had to recover the files to a different drive, as Disk Drill wouldn't allow me to recover them to the original drive (just said it didn't have enough space?!). It even found and allowed me to recover the lost HFS+ partition, of the erased drive. Not sure I can do anything with that, because I very much doubt the Apple system will allow me to just copy all the files back to the original drive, and then allow me to boot it, like it was!
But that's okay. The data files are what counts. Once I copy them back to the original drive, I will just reinstall the High Sierra OS. It wasn't being used as a boot drive, anyway, so it doesn't strictly need an operating system.
So yeah, I got real lucky this time... I don't know if DD can also recover a formatted drive... But if there's even a possibility "Data Rescue" can, that's very nice to know.
There is no way to "unformat" a drive (meaning undo a formatting). How did you do this? With Disk Utility under a normal boot, or with Disk Utility in Recovery Mode? Can you start up your Mac?
Pls. tell us the exact model iMac you have; if you can't boot your iMac but have your invoice and/or original box you can look there; if not but you know your serial number you may be able to look up the model at Check Your Service and Support Coverage - Apple Support. At last resort, the serial number is printed on the bottom of the iMac stand. (Do not post your serial number here, just the model.)
Depending on the model, it may be possible to put the iMac into Target Disk Mode, connect it to another Mac and potentially recover data that was erased during the formatting you did.
When you erase a drive, you also format it. If you don't, you don't complete the erasure:
Note the formats to choose from when erasing. Depending on other factors, you may have more than these four choices.
And no, you cannot "unformat" a drive. Erasing is erasing ... with no backups, your data is irretrievably gone.
Glad it worked out for you. That was a very close call.
Most of those recovered files are probably system related files. Does Disk Drill at least give you file types/extensions so you can tell docs, images, etc. apart all the kinds of system files?
I didn't even format it yet, just erased it. So the system won't even recognize the drive. But I'm afraid to format it now, in case it makes matters worse!
Can I undo an iMac's internal disk format?
