How to save dashcam footage after a crash, before loop recording erases it

Lock the clip first, then stop the camera from recording over it. The manuals for VIOFO, Garmin, Nextbase, Vantrue, BlackVue and Tesla all describe the same basic loop: when the card or its storage area fills, the camera writes over older unprotected video to make room. How long you have depends on card size and settings. Do the steps below in order, today.

Why the clip disappears, and what a locked file is

VIOFO’s A229 manual says that when space runs short, “loop recording will automatically overwrite the oldest files (one by one).” Garmin’s manual for the Dash Cam 46, 56 and 66W says the device overwrites the oldest unsaved video when the storage space for unsaved videos is full. Tesla’s owner’s manual says Dashcam and Sentry Mode record “in cycles” and footage “is continuously overwritten unless you save it.”

A locked file (called protected by Nextbase, an event or emergency file by Vantrue, 70mai and BlackVue, saved by Garmin and Tesla) is a clip the camera moves out of the normal loop. Cameras usually lock a file in two ways: automatically, when the G-sensor detects an impact, and manually, when you press a button. The manual button does not work the same way everywhere. VIOFO and Vantrue lock the file being recorded at that moment. Tesla saves the last ten minutes. 70mai’s A510 records a new 30-second clip starting 5 seconds before the press, and BlackVue’s DR970X manual describes the touch sensor as starting a manual recording.

Two limits matter after a crash:

• Protected space is finite. Nextbase says its cameras reserve about 30 percent of the card for protected files, and once that fills, the camera “starts overwriting the oldest Protected files.” That article covers Nextbase’s Series 2 range. Vantrue’s N4 Pro manual gives the same 30 percent figure for event files.
• Auto-lock is not guaranteed. Tesla’s manual says whether Auto saves a clip depends on factors such as the force involved and whether airbags deploy, and tells owners not to rely on it. A low-speed bump may not trigger the sensor, so lock the clip by hand even if you think the camera already did.

The first 10 minutes: what to do with the camera

1. Lock the clip now. Press the lock, protect, emergency or save control (brand steps below). If the crash was more than one clip ago, the button may not cover it, so go to step 2 quickly; the crash may still be in the normal loop files.
2. Stop new video from being written. Pause recording if the camera allows it, or turn the camera off. Then remove the card the way your manual says. BlackVue’s manual says to unplug the power cord before you take the card out; Garmin’s says to turn the camera off first, because removing the card while it is on can lose data; Tesla’s says to pause Dashcam before removing the flash drive “to avoid losing video footage.” One exception: if a Garmin is set to Promptly Delete unsaved video, its manual says it deletes all unsaved video each time it is powered off, so save the clip on the camera before you switch it off.
3. Do not format the card, and do not delete anything to make room. VIOFO’s manual says formatting deletes all data and it is unrecoverable. Tesla’s says Format USB Drive erases any existing content. The camera’s format reminder can wait.
4. Find the right files. Put the card in a card reader on a computer and open the event or locked folder for your brand (below). Check the normal loop folder too: if the camera never locked the clip, the crash may still be sitting there, unprotected.
5. Copy, do not move. Copy the original files to the computer exactly as they are. Do not rename, trim, compress, convert, or run them through an editing app. Many cameras record each camera angle as a separate file; copy every angle for the time window, and copy the minute before and after as well.
6. Make a second copy on a different device. An external drive, a second computer, or cloud storage. One copy is one failure away from none.
7. Write down the details using the note below.
8. Check the camera’s clock. Compare the time stamped on the video with your phone’s clock and record the difference. Daylight saving can throw it off: VIOFO’s manual notes that its time zone “must be manually adjusted for daylight savings,” and Vantrue’s N4 Pro sets time from GPS based on the time zone you chose. A clip stamped an hour off can still be useful; stating the offset up front heads off confusion about timing.

Copy this: your footage note

Fill this in while it is fresh and keep it with both copies.

FOOTAGE NOTE
Incident date and approximate real time:
Location (street, cross street, direction of travel):
Camera make and model:
Card or drive the files came from:
File names copied (every angle):
Folder each file was in (for example DCIM\Movie\RO):
Time shown on the video at the moment of impact:
Real time at that moment, per my phone:
Camera clock offset (camera minus real time):
Date and time I copied the files:
Where copy 1 is stored:
Where copy 2 is stored:
Anything edited or exported? (Originals untouched: yes / no)

If you want a check that the file has not changed since you copied it, you can record a SHA-256 hash of each original: on a Mac, shasum -a 256 filename.mp4 in Terminal; on Windows, certutil -hashfile filename.mp4 SHA256 in Command Prompt. Write the result on the note.

Brand by brand: how to lock and where the files are

Button labels and folder names vary by model and firmware. Each entry below is from the maker’s own manual for the named model; check your model’s manual if your camera differs.

Camera	How to lock or save the clip	Where to find it on the card
VIOFO (A229 Duo)	Press the lock button once while recording; the G-sensor also locks on collision; the optional Bluetooth remote locks the current file	DCIM\Movie\RO (loop files in DCIM\Movie, parking files in DCIM\Movie\Parking)
Garmin (Dash Cam 46/56/66W)	Hold the button that takes a photo from the viewfinder, or say “OK, Garmin, Save Video”; incident detection saves automatically	DCIM folders: 100EVENT (incident), 102SAVED (manual), 103PARKM (parked), 105UNSVD (unsaved, overwritten when full)
Nextbase (Series 2)	Press the Protect button on the bottom of the camera while recording, or in playback to protect an already recorded clip; impacts protect automatically	Protected files, in reserved space of about 30% of the card; the app lists them under Library, Protected Files
Vantrue (N4 Pro)	Short press the power button while recording; the G-sensor locks automatically	Event Video folder; file names contain _E_ (normal files _N_, parking _P_)
BlackVue (DR970X series)	Touch the sensor for a manual recording, if the touch sensor is enabled in the firmware settings; impacts create event recordings starting 5 seconds before the trigger	Use BlackVue Viewer’s event filter, which shows E (event) and I (impact while parked) files
70mai (A510)	Press the function button below the flag icon on the main screen; with emergency video enabled, a detected collision triggers it automatically	The A510 guide does not name the card folder; find the clip by its time stamp
Tesla (Model Y manual)	Touch the Dashcam icon, or honk with On Honk enabled, to save the last ten minutes	TeslaCam\SavedClips on the USB drive (unsaved video in RecentClips)

VIOFO. The A229 Duo manual says a locked file “will not be overwritten by the loop recording feature.” In playback you can also lock or unlock the current video.

Garmin. The manual warns that unsaved and Travelapse videos are not available when the option to promptly delete unsaved video is turned on. If your crash clip is not in 100EVENT, 102SAVED or 103PARKM, look in 105UNSVD immediately, before the camera overwrites it. On the camera itself, Gallery, Unsaved Videos lets you scroll to the time of the crash and choose Save, which keeps a three-minute clip.

Nextbase. Unprotected files keep being overwritten as usual. Each recording is saved twice, as FH (full HD) and FL (low resolution), with RH and RL for a rear camera; copy both versions of every angle. Protecting the clip buys time, not permanence, so copy it off.

Vantrue. The N4 Pro manual adds two cautions: lock recording does not trigger when loop recording is off or time-lapse is on, and once event files reach their 30 percent share, new ones overwrite the old.

BlackVue. The DR970X manual says that when the card is full, the camera records over the oldest videos first. Unplug the power before removing the card. In BlackVue Viewer, right-click a file and choose Download to copy it to a folder on your computer, and keep the original file name when the viewer asks for one. Avoid Export, which can cut a segment or drop the sound.

70mai. The A510 guide says each emergency video is 30 seconds: 5 seconds before the trigger and 25 after. So pressing it minutes after a crash will not capture the crash; copy the normal recordings from that time instead. The guide also says the camera will not record an emergency video while it is connected to the 70mai app.

Tesla. Tesla’s Model Y manual says the RecentClips folder holds up to 60 minutes of recorded content, and SavedClips holds recordings saved and renamed from it. Each saved clip has a separate video from each camera. If you were parked with Sentry Mode on, look in SentryClips; Tesla says the oldest Sentry clips are deleted when the drive runs low and cannot be retrieved. With the car in Park you can also review clips on the touchscreen by touching the Dashcam icon; Tesla says Dashcam recording pauses when you launch the Viewer. The Viewer can also delete clips.

Handing footage to police or an insurer

The rule is the same for both: give them the original file, and keep your own original.

1. Send a copy, keep the original. Hand over a copy of the untouched file on a USB drive, or by the upload link the officer or adjuster gives you. Keep the card or your first copy unchanged.
2. Send every angle and the files on either side of the impact, with their original names.
3. Include your footage note, especially the clock offset. It heads off questions about timing.
4. If you also send a short excerpt for quick viewing, label it as an excerpt and say the full original is available. App exports and trimmed clips are new files, not the camera’s original.
5. Write down who received it, when, and how (report or claim number, name, method).

How long police or insurers keep footage, and whether you must turn it over, depends on your state and your policy. Ask the officer or adjuster directly. A lawyer can advise on a specific claim.

If you were in New York, the New York accident report guide covers the report itself, and the New York accident video guide covers getting other video of the crash. If you need footage from someone else’s camera, post a free footage request or see how to get security camera footage from a business.

If someone posted a request on the footage board

If you saw a crash and a request on the footage board matches the place, date and time, the steps above apply to you too, and the clock matters more, because the person asking was not there to lock anything.

1. Lock and copy first, before you reply. The clip can be overwritten while you wait.
2. Check the match against the request: location, direction of travel, and time, adjusted for your camera’s clock offset.
3. Respond on the request’s page. The board forwards your note by email and keeps your email private until you both agree to connect.
4. Do not upload or post the footage on the board. It does not accept footage. Keep the original file unedited and hand a copy directly to the poster once you connect.
5. Treat any reward as a private agreement. The board does not hold or process rewards.

Want to hear about the next request near you? Register your dashcam for free alerts. Need footage yourself? Post a request.