Summary

"The camera shows live, but there's no footage when I go back to check" is a common and often unwelcome discovery — usually made only after an incident, when the customer needs the footage most. Unlike a "no signal" fault, which is immediately visible on the live view, a recording fault can run for weeks before anyone notices, because the live picture and the recorded picture are handled by separate parts of the NVR.

There are five broad categories of cause: recording schedule misconfiguration (recording only set for certain hours or days), storage problems (HDD full, failed, unformatted, or not detected), per-channel recording settings disabled, motion-detection settings preventing continuous capture, and genuine hardware or firmware faults. In practice, the first three account for the large majority of real-world callouts — most "the NVR isn't working" faults trace back to a setting rather than a broken component.

Because the failure is silent, the most valuable thing an installer can do — beyond fixing the immediate fault — is set a recurring reminder (or advise the customer) to spot-check playback periodically. A camera showing "no signal" gets noticed within days; an NVR that has quietly stopped recording, or is only recording 2 hours a day instead of 24, can go unnoticed for months.

Key Facts

Quick Reference Table

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Symptom Most Likely Cause First Check
Live view fine, zero recorded footage on any channel Recording schedule not applied / disabled globally Check global recording schedule settings
Recording works for some hours/days only Schedule set to partial hours, not 24/7 Review per-day/per-hour schedule grid
One channel not recording, others fine Per-channel record toggle disabled Check individual channel recording settings
Recorded footage stops after a few weeks HDD full, set to "stop when full" not overwrite Check HDD capacity and overwrite setting
No footage despite full schedule and enabled channels HDD failed, uninitialised, or not detected Check HDD status in NVR menu
Motion events missed during testing Motion sensitivity/zone set too low or too small Increase sensitivity, redraw detection zone
Playback shows footage on wrong date NVR clock drifted or reset after power cut Check/reset system date and time, check RTC battery
Recording quality drops or channels skip frames Bandwidth exceeds NVR processing capacity Check total bitrate vs NVR spec, reduce resolution/fps
All recording stopped after recent power cut Corrupted recording database, unformatted new HDD Check HDD health, reformat if replaced
Recording resumes after reboot but stops again later Firmware bug or failing HDD (intermittent) Update firmware; run HDD health/S.M.A.R.T. test

Detailed Guidance

Fault-Finding Decision Tree

START: NVR shows live video but footage is missing/incomplete
│
├─ STEP 1: Check HDD status in NVR menu
│   ├─ HDD shows "error" / "abnormal" / "not detected"
│   │   → Replace HDD (surveillance-grade); reformat in NVR menu
│   ├─ HDD shows "uninitialised" (new/replacement drive)
│   │   → Format the HDD from within the NVR menu, not a PC
│   └─ HDD shows "normal" → continue to Step 2
│
├─ STEP 2: Check HDD capacity/usage
│   ├─ HDD is full or near-full
│   │   ├─ Overwrite mode enabled → oldest footage should be
│   │   │   deleting automatically; confirm this is happening
│   │   └─ "Stop recording when full" enabled → THIS IS THE FAULT
│   │       → switch to overwrite, or add storage/reduce retention
│   └─ HDD has ample free space → continue to Step 3
│
├─ STEP 3: Check recording schedule (per channel)
│   ├─ Schedule not set / set to "off" for some hours or days
│   │   → Configure 24/7 continuous schedule (or as required)
│   ├─ Schedule correct but channel still not recording
│   │   → Check per-channel "record enable" toggle (separate
│   │       from schedule on many NVRs)
│   └─ Schedule and toggle both correct → continue to Step 4
│
├─ STEP 4: Check recording MODE (continuous vs motion vs event)
│   ├─ Set to motion-only, but "missing" footage is of a
│   │   static/quiet period → this may be correct behaviour;
│   │   confirm customer's expectation matches configured mode
│   ├─ Set to motion-only, motion clearly occurred but wasn't
│   │   captured → check sensitivity and detection zone coverage
│   └─ Set to continuous, still not recording → continue to Step 5
│
├─ STEP 5: Check system date/time and bandwidth
│   ├─ Clock is wrong/drifted → footage may exist under the
│   │   wrong timestamp; correct clock, check RTC battery
│   ├─ Total camera bitrate exceeds NVR's rated bandwidth
│   │   → reduce resolution/fps or upgrade NVR
│   └─ All checks pass, still no recording → check for firmware
│       update; if unresolved, suspect NVR hardware fault
│       (main board / storage controller)

Storage Faults — the Most Common Root Cause

Storage-related faults account for the majority of "not recording" callouts once schedule misconfiguration has been ruled out. Work through this checklist on site:

  1. Check HDD status in the NVR menu (usually under System / HDD / Storage). Most NVRs report health as normal, abnormal, or not detected.
  2. Check free space and overwrite policy. A drive reporting "normal" but 0% free space with overwrite disabled will accept no new footage — this looks identical to a hardware fault from the customer's perspective but is a one-click settings fix.
  3. Confirm the drive is surveillance-rated. Desktop HDDs are built for occasional reads, not continuous 24/7 writes, and commonly fail within 1–2 years of NVR service. If a non-surveillance drive is fitted and has been in service for over a year, budget for a replacement even if it's currently reporting normal — early failure is common.
  4. Run the drive's S.M.A.R.T. health test if the NVR menu exposes it — reallocated sector counts and pending sector counts are early warning signs of imminent failure, well before the drive stops working entirely.
  5. Check for a corrupted recording database after any unclean shutdown (power cut without a UPS). Some NVRs will report the drive as healthy but be unable to index existing recordings; a full reformat (after confirming footage is unrecoverable or already backed up) resolves this, at the cost of losing existing footage.

Recording Schedule and Per-Channel Settings

Recording schedules on most NVRs are configured as a weekly grid (day × hour), often defaulting to specific windows rather than 24/7 on first setup — particularly on hybrid systems configured by a previous installer for motion-only recording to save storage. Confirm with the customer what coverage they expect (continuous vs motion-triggered) and configure accordingly, then verify by checking the timeline/calendar view in playback mode shows continuous colour-coded recording blocks for the expected period.

Separately, check the per-channel record enable toggle — on many NVR interfaces this exists independently of the schedule grid, and a channel with a perfectly configured 24/7 schedule will still not record if this toggle has been switched off (commonly happens accidentally during menu navigation, or is left off from initial commissioning of a channel that wasn't yet connected).

Motion Detection Configuration

If motion-triggered recording is used (common to conserve storage on longer retention periods), verify:

Bandwidth and Processing Limits

Budget NVRs have a maximum total bandwidth they can process across all channels simultaneously. If the sum of all camera bitrates exceeds this limit, symptoms range from dropped frames, to reduced recording resolution, to specific channels silently failing to record while others continue normally. Check the NVR's rated maximum throughput against the actual configured bitrate of all connected cameras (visible in each camera's settings, or estimated from resolution/compression per the manufacturer's typical bitrate table) — this is a common and often overlooked cause when a system has had cameras added incrementally beyond its original specification.

After a Power Cut

Sudden power loss during an active write cycle is a well-known cause of recording faults that persist after power returns:

Frequently Asked Questions

The NVR says the HDD is "normal" but there's still no footage — what else could it be?

Check overwrite policy and free space next — a technically "normal" (healthy) drive that is full, with overwrite disabled, will refuse new recordings while still reporting no hardware fault. After that, check the recording schedule and per-channel record toggle, since both are common causes that leave the HDD reporting perfectly healthy throughout.

How do I recover footage from a corrupted or reformatted HDD?

If the HDD itself is mechanically sound but the recording index is corrupted, some NVR manufacturers provide a repair/rebuild database function in the menu — try this before reformatting, since reformatting will erase all existing footage. If footage has already been lost through a reformat, specialist data recovery software or a data recovery service may be able to recover fragments from the raw drive, but success is not guaranteed once the file system has been rewritten. Prevention (UPS, surveillance-grade HDD, RAID for critical applications) is far more reliable than recovery.

Should I use motion-only or continuous recording?

Continuous (24/7) recording is generally preferred for security applications because motion detection can miss slow-moving subjects, small objects at distance, or events at the edge of a poorly-configured detection zone — and BS 8418-compliant monitored systems expect reliable continuous capture. Motion-triggered recording is a reasonable compromise where storage budget is limited and the customer accepts the higher risk of a missed event; if used, test it thoroughly by walking through each camera's field of view at the speed and distance of a realistic scenario, not just standing directly in front of the lens.

How often should I check that an installed system is actually recording?

Because recording faults are silent, it's good practice to build a check into the handover and any maintenance visits: search playback for footage from the previous 24–48 hours across every channel, confirm the timeline shows continuous (or expected motion-triggered) blocks, and check HDD free space and overwrite policy. For customers without a maintenance contract, advise them to spot-check playback monthly — a five-minute task that catches faults long before an incident makes the gap critical.

Regulations & Standards