Reinstalling Windows over the top of your own data is one of the most recoverable disasters there is, provided the machine is switched off quickly. This page explains what a reinstall actually writes, why deleted partitions are not the catastrophe they look like, the difference an SSD makes to your window, and what to do in the ten minutes after you realise.
One drive is £300 + VAT, or £400 + VAT if BitLocker was on, and a reinstall is a logical job with no fix, no fee. A reinstall marks the old space free rather than erasing it — so switch the machine off now, because everything written since is what costs you files.
A reinstall is not one event. The option that was chosen and the drive it landed on together decide whether this is a routine job or a difficult one, so start by working out which of these you did.
The gentlest option. Windows is replaced while the user folders are left in place, and normally nothing needs recovering at all. Where files do go missing it is usually because they lived outside Documents and Desktop, or because the account they belonged to was not carried over. Frequently these are still on the disk in full.
Windows deletes the account folders and lays down a fresh install. On a mechanical hard drive the old data is still physically present and generally recoverable. On an SSD, if the option to clean the drive was also chosen, the controller will have cleared those blocks and the honest answer is that they are gone.
The installer was booted, the partition selected, and Windows written on top. This one is often better than people fear. A standard install writes perhaps twenty to thirty gigabytes of system files, and everything they did not sit on top of is still there to be found.
Somebody removed the existing partitions to get a clean slate and then created new ones. That destroys the map of the disk rather than the contents, and the old file system structures can normally be located again and rebuilt. It looks catastrophic and it usually is not.
A machine with two disks, and the installer went to the wrong one. Straightforward and hopeful, provided the machine is switched off now. The damage is limited to whatever the install actually wrote, and the rest of that disk is untouched.
The worst version, and by some distance. Every day of ordinary use writes updates, browser caches, downloads and temporary files across the free space, which is exactly where your old data lives. It is still worth a look, but it becomes a matter of what has survived rather than what can be brought back.
The instinct after a reinstall is that everything has been erased, and that is not how it works. A Windows installation writes its own files onto the drive and marks the rest of the space as free. Free is not the same as empty. Your old documents, photographs and emails are sitting in that free space, complete, until something else is written on top of them.
So the question is never really whether the data survived the reinstall. It is how much has been written since, and where it landed. A machine switched off the moment somebody realised what they had done is a good job. The same machine used for a fortnight of email and browsing is a partial one, because Windows updates alone will have scattered several gigabytes across the disk.
Deleting the partitions during setup sounds worse than it is. The partition table is a small structure at the front of the disk describing where each volume starts and ends. Removing it takes away the description, not the contents, and the old file system can normally be found again by looking for its own structures further into the disk. It is one of the more reliably recoverable versions of this problem.
This is where the answer divides, and it is worth understanding before you spend anything. A mechanical hard drive keeps whatever is written on its platters until new data physically replaces it, which is why a reinstall on a hard drive leaves so much intact. A solid state drive behaves differently. When Windows marks blocks as free, it also tells the SSD, and the drive's controller then erases those blocks in the background so they are ready for the next write. That is TRIM, and it is doing exactly what it was designed to do.
The practical effect is that on an SSD the window is short and it closes on its own. A reinstall that ran an hour ago may still hold a great deal; the same drive left powered on overnight has usually finished clearing itself. If the install also chose to clean the drive fully, or if the SSD was told to secure erase, the data has gone in a way no laboratory can undo. Anyone promising otherwise is selling hope.
There are exceptions and the diagnostic finds them. Some external and USB-connected drives never receive TRIM commands. Some older or cheaper SSDs handle it lazily. A drive that was disconnected quickly may have been interrupted mid-clear. None of that is worth guessing at from the outside, which is why the assessment costs nothing.
Stop using the machine. Not later, now. Shut it down properly if you can and leave it off, because every minute it runs writes something somewhere.
Do not install recovery software onto the affected drive. The installer itself is written into the free space you are trying to rescue, and it is entirely possible to overwrite the very files you were about to look for. If you want to try software yourself, run it from a different machine with the affected disk connected as a second drive, and always send its output somewhere else.
Do not restore a backup onto the same disk, do not let Windows finish setting itself up, and do not sign in and start downloading things to see what is missing. Above all, do not reinstall again to try to put things back, which is a surprisingly common second move and it doubles the damage.
If the machine holds two drives and only one was reinstalled, unplug the other one before doing anything else. That single step has saved a good many jobs.
One drive is £300 + VAT, hard disk or SSD alike, fixed in writing before any work begins. If the drive was encrypted with BitLocker, it is the encrypted band at £400 + VAT and the recovery key is needed. Memory cards and USB sticks are £250 + VAT. A machine with an array in it is from £500 + VAT, rising with the number of disks. Forensic work with a written report is £800 + VAT, and a binary image with deleted-file extraction and no report is £400 + VAT.
A reinstall is a logical job, so it carries no fix, no fee. If nothing usable comes back, there is nothing to pay, and the diagnostic beforehand costs nothing either way. The published exclusions from the guarantee are electronic and mechanical failures, chip-level work, DVR jobs and forensic jobs, none of which apply to a healthy drive that has simply been written over.
The free diagnostic closes two working days after the drive is booked in. On a reinstalled drive it does something more useful than usual: it tells you what is actually still there, in the form of a listing, before you commit to anything. Recovery normally follows within two to four working days of the figure being agreed. Large drives that need reading end to end for file signatures take longer, and you are told if that applies.
Take the disk out of the machine and send that alone — not the tower, not the laptop, not the all-in-one. A repair shop will free one in a few minutes if you would rather not open the case. If the machine has two disks, send the one that was reinstalled onto, and say so clearly, since the difference matters. An external drive travels whole and sealed in its own enclosure, a NAS travels whole with its disks in the bays, and a Fusion Mac needs both drives labelled. For a RAID or a server, send the member disks only, marked with their bay order.
Write down which version of Windows was installed, which option was chosen, and roughly how long the machine was used afterwards. That is genuinely the difference between a confident answer and a guess. Post it to Oxford Data Recovery, John Eccles House, Oxford Science Park, Robert Robinson Avenue, Littlemore, Oxford OX4 4GP, or bring it in on a weekday between 9:00am and 5:30pm; it is about fifty-five miles from Coventry down the M40. There is no counter in Coventry and no collection service.
Almost nobody reinstalls Windows for fun. It is the last step of a bad week: the machine had been slow, then it started failing to boot, then a helpful person suggested a fresh install, and by the time anybody thought about the photographs the setup screen had already moved on. Occasionally it is a new drive fitted in a shop and the old one reused before the data came off it, and occasionally it is a work laptop reimaged by an IT department while somebody had files outside their profile.
None of those need to be the end of it. The disk is nearly always healthy, the old contents are nearly always still down there, and the only real enemy is time spent using the machine afterwards.
Windows wrote its own files and left the rest alone. Switch the machine off and the diagnostic will tell you exactly what is still down there.
Small media is the simplest thing in the world to send, and the post treats it far better than a week in a coat pocket or a glovebox does. A padded envelope given to a courier in Warwickshire on a weekday tends to be booked in at Oxford the next morning, and you are told the moment it lands.
As a rule the storage comes out and the machine stays where it is. That applies to a laptop, a tower, an iMac and to the recorder sitting under a counter. Taking equipment apart is not something this bench does, and a repair shop will free a drive in a few minutes. Two things go the other way: an external drive stays sealed inside its own case, and a NAS travels as a complete unit with its disks still in their bays. A Fusion Mac is a third case — both of its drives come out and travel together, each one labelled. The single situation nobody can work around is memory soldered flat onto a mainboard, which is how Apple Silicon Macs and a good many slim laptops are built: if the storage will not unbolt, there is no parcel to send.
↓ Print the shipping & booking-in form (PDF)
Put Oxford Data Recovery on the label. From Coventry it is roughly fifty-five miles straight down the M40, about an hour if you would rather drive it in than post it. Either way you are told the moment it is logged, and the free diagnostic finishes two working days later.
Unsure what ought to go in the box? Ring 0800 689 0668 before you seal it, or work through the free online diagnostic and let it do the asking.