Is a factory reset going to completely wipe out all data? Two users will be asking this same question in totally different contexts. One user needs all of the files gone so they can sell their laptop; the other has wiped out a computer by doing a "factory" restore and now wants everything back. This question is being asked from two sides of the coin, but with some good news: the real answer works for both. It depends entirely upon the type of storage that is present (spinning disk, hard drive) versus an SSD.
Windows’ “Reset this PC” (with the option for Remove everything) or a basic install-on-top-of-an-old-system will be much quicker than when you copied all of your files, so that tells you something. A terabyte of file space is not being wiped clean; rather, an entirely new operating system is being laid down with completely blank bookkeeping. Your photo directory no longer exists, but those photos are largely still going to sit there on the platters or chips until something else decides to use that same storage location.
This is one reason why there are two truthful answers to this question. The answer to the seller: no, you cannot be sure that simply resetting will completely erase everything from your computer. This is why Windows also gives users an option to "clean the drive fully", which is much longer than a quick reset. The answer to the regretter: for the same reason, there is often real hope, but how much depends on the hardware.
Old data in a standard hard drive remains in place until something actively overwrites this information. In most cases after you complete a quick Windows reset on a big, half-empty drive, Windows will take up very little space and leave large parts of the previous years of your data intact (though without an index) below where the new operating system has been installed. Professional recovery software reads every sector of the disk. It will ignore the newly created empty index which Windows created for itself. The professional recovery software then uses file signatures and remnants of any previously used file management systems to reconstruct your lost data.
Recovery odds are directly related to what happens after the reset. A machine reset in error yesterday and turned off: recovery is wonderful. A machine reset in error last month and used daily (updates, downloads, browser churn, etc.) has been overwriting your past a little bit each session. If you just reset in error: stop using the machine now; power it off, and the deleted file bench takes care of the rest.
The comfortable half of this story ends with solid-state drives. After resetting or formatting most new SSDs, the OS will send TRIM commands to the drive indicating which blocks are now available. Then the drive itself (for self-maintenance purposes) will erase these blocks in the background (usually within minutes to hours). There's no software setting you should feel guilty about; it's just how the technology maintains performance.
Honestly then: most user data will normally be unrecoverable if a complete reset has occurred on a TRIM-enabled SSD, by us or anyone, regardless of what more aggressive advertisements may have claimed. The real possibilities for recoverability exist at the edges; i.e., resets that were either interrupted or did not completely finish, drives that are configured so as to preclude TRIM from ever occurring on them, or files which resided on a second drive/partition other than the one being reset. While those true edge cases do represent legitimate reasons for the use of the free diagnostic, we'll tell you bluntly: a typical complete reset of the system SSD generally means goodbye. Sellers should read that same sentence with a smile.
Reset by accident? Turn it off right now. Every time you use your computer or laptop, more of its previous contents are overwritten. There will probably still be files left on your hard drive after the factory reset. If your device has an SSD instead of an HDD, then you can find out whether we think that you have a case at all: we give an honest assessment of the edge cases and will tell you quickly if it is not worth your money (the diagnostic is free regardless of outcome). Recovery is in the standard £300 + VAT band. No charge for most jobs where we do not recover any data. One note: this guide covers Windows PCs and laptops; phone and tablet recovery is not a service we offer.
Selling or recycling? Do the complete opposite of everything listed above; use the full "clean the drive" reset option, and for any item containing business/client information, consider certified data destruction; since, as shown in this entire web page, a simple "factory reset" does not always keep its promise.
Turn the device off & take the hard drive out of it. Any local computer shop can do this for you in minutes. Once you receive a quotation to fix the issue, bring / send the hard drive to us as it is. Hard drives are recovered easily from resets, whilst for SSDs we will quickly tell you if they are recoverable with an honest yes/no. Diagnosis will be free, all other costs are fixed in writing at £300 + VAT & on most jobs there won’t be a charge unless your files come back.