Test an SD card after formatting for drone footage

You formatted an SD card and are about to copy drone footage to it. A successful format only prepares the card's file system. It does not prove the card has its advertised capacity or that all of its storage can save and read data reliably.

For a more thorough check, use the Fake USB & SD Check. It fills a USB drive or SD card with test data and reads that data back. This can expose a card that reports more space than it really has, but it will write across the card, so do not run it on a card that contains the only copy of your footage.

Retest the card before copying footage

1. Copy any footage or other files on the card to a separate, verified location. The capacity test writes test data to the selected media. Use an empty card, not one with the only copy of important files.
2. Connect the card to a computer with a reliable card reader. Open the Fake USB & SD Check in Chrome or Edge on a computer. The tool has reduced or no access in other browsers, and it does not work on a phone.
3. Select the removable card carefully and run the capacity check. Check the drive name and reported size before proceeding. Keep the reader connected, and do not remove the card or shut down the computer while the test is writing or reading.
4. When the read-back check finishes, review whether the data was read correctly and whether the usable capacity matches what you expect. If the test reports errors or stops early, do not trust the card with a flight recording.
5. After a successful test, format the card in the drone or its camera. Then copy a short, nonessential video to the card, open it from the card, and check that it plays before transferring important footage.

A full-capacity check can take much longer than a quick format, especially on a large or slow card. If you are short on time, do not start it just before a flight. Use another card you have already tested instead.

What the result means

The test writes and reads the card successfully

The card passed this full-capacity write and read-back check. That is useful evidence that the tested space could store and return data during this run. It does not guarantee that the card will never fail, that it can sustain the video bitrate your drone needs, or that a particular footage copy is complete.

The test finds errors or less usable space than expected

The card may have fake capacity, damaged storage, or a connection problem. A card that claims a large capacity but cannot read back all the test data is not safe for footage. Recheck it with a different reader and port only after ruling out a loose connection. If the same problem returns, stop using it for recordings.

The test is interrupted or the card disconnects

An interrupted run does not count as a pass. The reader, port, adapter, card, or computer may have lost connection or power. Do not assume that a partial test checked the whole card. Reconnect the card and repeat the test only after backing up anything you need.

The card passes, but footage will not copy or play

The capacity test checks storage behavior, not every issue in your recording workflow. A card can pass a read-back test but still be too slow for a drone's sustained video recording, or the drone may need a particular format. Check the drone manufacturer's supported card type and speed rating. For a recording that stops or drops frames, see what to check when a camera says the card is too slow.

How to fix a problem before copying

1. Check the reader and connection. Remove and reseat the card, then try a different USB port or a known-good reader. Avoid testing through a loose adapter or hub if the card disconnects during writing.
2. Back up anything readable. If the card still opens, copy needed files elsewhere before formatting or testing again. Do not use the capacity test to recover footage, and do not write new files to a card that may be failing.
3. Format the card in the drone. The drone can prepare the file system it expects. Formatting erases the card, so do this only after you have saved any files you need. If you must format on a computer, Windows 11 has the card under File Explorer › This PC. On macOS, open Disk Utility › View › Show All Devices, select the card's volume, then choose Erase. Use a format supported by your drone, and check its instructions first.
4. Repeat the full test only on an empty card. After backing up and formatting, run the capacity check again if you need to confirm the whole card. A quick format alone does not verify every part of its storage.
5. Try a known-good card. If the card keeps failing, use a replacement that meets the drone's requirements. Do not rely on a card with repeated read-back errors for footage you cannot recreate.

Check the footage copy separately

The capacity checker writes its own test data and reads it back. It does not compare your drone's original files with the files you copied, and it does not test how the drone records video. After formatting the card in the drone, make a short test recording or copy a small sample of footage. Check that the file size looks plausible and that the clip opens and plays from the card or destination drive.

For important footage, keep the original and the copy until you have checked the copied files. A passing card test is one useful check, not a substitute for a second copy of irreplaceable video.