On an encrypted device it throws away the key, and the data becomes mathematically unreadable in seconds. On an unencrypted one it marks space as free and leaves the contents sitting there. The difference decides whether anything can be recovered.
Modern phones and Macs encrypt by default, so a reset discards the key and ends the matter. Older devices and many Windows installs simply mark the space reusable, which is a very different outcome.
iPhones, iPads, modern Android phones, Macs with a T2 chip or Apple Silicon, and any Windows machine with BitLocker enabled all encrypt storage by default. On these, a factory reset performs what is called a crypto-erase: it discards the encryption key rather than overwriting the data. The bytes remain on the flash, but without the key they are indistinguishable from noise, and no amount of laboratory work changes that.
This is genuine, immediate and irreversible. It is also the correct behaviour — it is what allows a phone to be wiped in seconds rather than hours — but it does mean that on these devices “does a factory reset delete everything” has a simple answer: yes.
On an unencrypted drive, a reset or a quick format rewrites the file system structures and marks the old space reusable. The files themselves are untouched until something writes over them. This covers a great many Windows PCs where BitLocker was never enabled, most external drives, older Android devices without full-disk encryption, and any machine reinstalled from media rather than reset.
Windows adds a wrinkle worth knowing: its reset offers “remove my files” and “fully clean the drive”. The first is fast and leaves data recoverable; the second overwrites and takes hours. People in a hurry almost always choose the first, which is good news if the reset was a mistake.
iPhone and iPad: gone. Crypto-erase, no recovery route. Modern Android: gone in almost all cases, for the same reason. Mac with T2 or Apple Silicon: gone. Older Intel Mac with a removable drive and no FileVault: often recoverable. Windows PC without BitLocker, reset with “remove my files”: frequently recoverable. Windows PC with BitLocker, or reset with “fully clean the drive”: gone. External hard drive quick-formatted: usually recoverable. SSD where TRIM has run: usually not.
Power the device down rather than continuing through setup, because setup itself writes steadily. Don’t restore a backup onto it — that writes across exactly the space you want read. Don’t install recovery software onto the affected drive.
Where the data is still physically present, a single drive is from £300 +VAT after a free 48-hour diagnostic and a written quote, and most jobs are no fix, no fee. Where the device crypto-erased, we will tell you at the diagnostic rather than take the job — there is nothing to recover and no honest way to charge for looking.
On an encrypted device, yes. iPhones, modern Android phones, T2 and Apple Silicon Macs and BitLocker-enabled PCs perform a crypto-erase — the encryption key is discarded and the data becomes unreadable immediately. On unencrypted devices the space is simply marked reusable and the data often survives.
Frequently, if BitLocker was not enabled and you chose “remove my files” rather than “fully clean the drive”. The fast option rewrites the file system and leaves the data in place. The thorough option overwrites it and takes hours, and after that there is nothing to recover.
Almost never on a modern phone. iPhones and current Android devices encrypt by default, so a reset throws away the key and the data is mathematically unreadable regardless of the flash still holding it. Cloud backups and any memory card are the realistic routes.
Power it off rather than continuing through setup, which writes steadily. Don’t restore a backup onto it and don’t install software onto the affected drive. Where data survives, the first hour matters far more than anything you do later.
A single drive is from £300 plus VAT after a free 48-hour diagnostic and a written quote, with most jobs no fix, no fee. Where the device crypto-erased there is nothing to recover, and we will tell you that at the diagnostic rather than charge you to find out.