A recorder writes in a loop, so the first question is how long you have before the footage you need is written over. The arithmetic is simple and worth doing now — then take the disk out of service, because every hour it keeps recording is an hour of older material gone.
$ mdr triage /dev/sdb → Device: Hikvision NVR HDD · 6 TB → Status: FOOTAGE LOOPED OVER — oldest blocks → Target: 09 Feb, 22:15–00:45 · cam 5 $ mdr engineer-working → Read-only image: taken · recorder halted in time → File system: Hikvision layout · parsed → Streams: H.265 rebuilt by timestamp $ mdr verify → ✓ channel 5 — 2h 30m recovered → ✓ exported — MP4 + timestamps → ✓ footage recovered — incident captured
DVRs and NVRs record in a loop. The moment the disk fills they begin writing over the oldest material, so every hour the system stays powered is an hour of older footage gone. If the recording matters, take the disk out of service now.
This is the only question that matters in the first hour, and the arithmetic is easy to do yourself.
A recorder holds a fixed amount of disk and writes continuously. Divide the capacity by how fast the system writes and you have your window. Four cameras at 1080p on continuous recording will typically fill a 2TB disk in somewhere between one and three weeks. Eight cameras, or higher resolution, or a higher frame rate, and that can drop to days.
Motion-triggered recording extends it considerably but unpredictably — a quiet week buys you a month, a busy one buys you five days. The practical consequence is that if an incident happened three weeks ago and the system has been running since, the footage may already have gone regardless of what anyone does. If it happened last night, you have time, but not much of it.
The single commonest way CCTV footage is lost after the incident.
Recorder disks are large and mostly full of nothing relevant, so targeting matters.
As precisely as you can, and then a margin either side. The exact moment of an incident is rarely where people first think it is, so we export wider than asked.
Channel number if you know it, or a description of what it covers. Separating one channel from seven others is straightforward when we know which one.
The format is manufacturer-specific, so this determines the approach before the disk arrives. A photograph of the label is fine.
If the system ran on after the incident, say so — it changes what is realistically still there and we would rather set expectations honestly at the start.
One of only three services here that works differently, and the reason is worth explaining.
CCTV, DVR and NVR recovery is £800 +VAT flat with a 50% deposit, confirmed after a free 48-hour diagnostic.
Almost everything else on this site runs no fix, no fee. Recorder work does not, because the effort is identical whether or not your footage survived. Reverse-engineering an undocumented video format, separating the channels and rebuilding the frame order takes the same days regardless of whether the window you need was overwritten three days before the disk arrived. Charging only on success would mean charging the customers whose footage survived for the work done on the ones whose did not.
What we do instead is tell you honestly at the diagnostic what the retention arithmetic suggests, so you can decide before committing. Footage comes back as MP4 with timestamps visible, playable without the manufacturer’s software.
Get the device to us with a short note on what happened. The diagnostic that follows costs nothing, and the figure that follows it is fixed in writing before any work begins.
Nothing can begin until the device is on the bench, which makes this the only step that needs anything from you. Pack it properly, put your details in with it, and send it over. What follows is a free diagnostic and a written figure, in that order.
Posting it? Use something tracked and insured — whatever is on the drive is worth considerably more than the postage. Bringing it in? Weekdays, 9am to 5:30pm, and it still wants packing as above for the journey.
Tell us what the device is, what it is doing, and anything already tried — an engineer will come back with a realistic view of the odds and a price band, before you commit to posting anything.
We’ll be in touch shortly. If it’s urgent, call 0161 871 0788.
The things people ask us most before sending a recorder or card in.
Divide the disk capacity by how fast the system writes. Four cameras at 1080p continuous will typically fill 2TB in one to three weeks; eight cameras or higher resolution can cut that to days. Motion-triggered recording extends it unpredictably.
Usually. DVRs write to ordinary hard drives in proprietary undocumented formats, so the disk is imaged read-only and the video carved out by structure rather than read as files. Where the recorder itself died, the disk and its footage are generally untouched.
No. Windows cannot read the proprietary format and assumes the disk is blank, which is why so many recorder disks arrive here already initialised. Decline the prompt and disconnect it.
Yes, and telling us in advance genuinely helps. Timestamps are embedded in the video structure rather than file metadata, so a particular window can be targeted and one channel separated from the others recorded alongside it.
MP4, so it plays without the manufacturer’s software, with timestamps preserved and visible. That matters when it is being handed to an insurer, a solicitor or the police.
£800 plus VAT flat, confirmed after a free 48-hour diagnostic. It takes a 50% deposit and sits outside no fix, no fee, because the reverse-engineering effort is the same whether or not the footage survived the overwrite loop.
A free diagnostic, footage recovered by camera and time from a DVR, NVR or SD card — even a failed recorder — and exported as standard files for your insurer or the police. Get in touch.