How to check an SD card before using it in a dashcam

A dashcam card can look normal and still have less storage than its label claims. A counterfeit or failing card may record briefly, then stop, overwrite footage early, or produce unreadable clips when you need them.

Before putting a card in the car, check whether it can store and read back data across its capacity. TooLab's Fake USB & SD Check can help find cards that report more storage than they really have. You will need a computer and a card reader.

Check the card before using it

1. Back up anything on the card that you want to keep. The test writes data to fill the storage, so use an empty card or one whose contents you can erase. Connect it to your computer with a card reader.
2. Open the Fake USB & SD Check in Chrome or Edge on a computer. This tool needs the browser's supported access to a connected drive. Other browsers may offer a reduced version or no access.
3. Select the SD card when the browser asks you to choose a drive. Check the drive name and capacity carefully so you do not test another connected storage device by mistake.
4. Run the check and let it finish writing and reading back the test data. Keep the computer awake, leave the card connected, and do not use or remove it while the test is running. A large card can take a while.

For a microSD card, use the adapter or reader you plan to use for the test. If the card is not listed, reconnect it and check that the reader recognizes it. The tool works best in Chrome or Edge on a computer, not a phone.

What the result means

The full test completes without read-back errors

The card was able to store and retrieve data across the tested capacity. That is a good sign that it is not falsely reporting a much larger size. It does not guarantee the card will last, work with your particular dashcam, or keep up with continuous recording.

The test finds errors or less usable space than expected

Some of the storage may be unreliable, or the card may be reporting more capacity than it can really hold. Do not trust it with important footage. Repeat the check once after reconnecting the card, ideally with another reader, to rule out a loose connection or reader problem.

The test stops before finishing

A disconnected reader, a browser permission issue, a computer going to sleep, or a failing card can interrupt the check. Reconnect the card and try again in Chrome or Edge. If it repeatedly stops at the same point, treat the card as unreliable.

The reported capacity is slightly smaller than the label

A small difference does not by itself mean the card is fake. Manufacturers and computers can report capacity using different units, and formatting uses some space. Pay attention to whether the tool can write and read back the data, not whether every displayed number matches the label exactly.

What to do if the check fails

1. Try another card reader. A worn adapter, loose connection, or faulty reader can interrupt data transfers. Use a different reader and USB port, then run the check again.
2. Check the card's lock switch. A full-size SD adapter may have a small write-protect slider on its side. Move it to the unlocked position, reconnect the card, and try again.
3. Close apps using the card. File browsers, backup programs, and media tools can interfere with access. Close them before reconnecting the card and repeating the test.
4. Test the speed if the capacity check passes. Use the USB & SD Speed Test to measure the card through your reader. Compare the result with the speed class or minimum card requirement in your dashcam's manual. A browser speed test is not a guarantee of sustained recording speed.
5. Replace a card that fails again. If errors return with another reader, do not use the card for dashcam footage. Return it to the seller if it is new, or replace it if it is old or worn.

Prepare a card that passes

Check the dashcam manual for the supported card type, maximum capacity, and minimum speed class. A card can pass a capacity check and still be incompatible with the camera. Some dashcams also work best with cards designed for repeated recording, rather than cards intended mainly for occasional file storage.

After the card passes, put it in the dashcam and use the camera's own format option before recording. The camera can prepare the file system and folders it expects. Then record a short clip, play it back on the camera, and confirm that recording starts and continues normally. If the camera reports an error, follow its card requirements rather than assuming the capacity test proves compatibility.

The Fake USB & SD Check tests whether data can be written and read back. It cannot predict how long the card will last, prove that it can handle every recording condition, or recover footage already lost. The check runs in your browser, and the test data stays on the connected card.