How to check a new memory card before a trip
Check a new SD card's speed, camera compatibility, and basic operation before you leave, so you can catch problems while there's time to replace it.
A new memory card can look fine in its package but still be too slow for your camera, fail to work with its format, or cause recording errors. Finding that out at home is much easier than discovering it on the first day of a trip.
Test the card's read and write speed on your computer, then try it in the camera you plan to use. The USB & SD Speed Test checks real transfer speed, but it cannot prove the card's full capacity or guarantee it will keep working over time.
Check the memory card
- Insert the card into a compatible reader and connect it to your computer. If you use a full-size SD adapter, check that its lock switch is not set to locked. Find the card in File Explorer under This PC on Windows 11, or in Finder under Locations on macOS.
- Open the USB & SD Speed Test. Select the card if the page asks you to choose a drive, then run the test and follow its prompts. Leave the card connected until the test finishes.
- Note the read and write results. Write speed matters when the camera saves photos or video; read speed affects how quickly you can copy files to your computer. If the result is unexpectedly low, repeat the test once with the card directly connected, not through a hub.
- Put the card in your camera and use the camera's own format command if the card is new and empty. Formatting erases data, so check the card first if you have already saved anything on it. The exact menu name varies by camera, so use its manual if you are unsure.
- Take several photos, record a short video using the quality setting you expect to use on the trip, and play the files back in the camera. Then copy a few files to your computer and open them to confirm they are readable.
What the result means
The speed looks reasonable and the camera records normally
The card and reader are working together at the moment, and the camera can save and play back files. This is a useful basic check, not a guarantee against future failure. Before traveling, copy any important photos elsewhere and consider carrying a spare card.
The card is slower than its label suggests
The reader, adapter, port, or computer may be limiting the result. A card's printed rating may describe a maximum or a specific kind of performance, while the test reflects the card-reader connection you used. Try another compatible reader or port before deciding the card itself is slow. For video, also check the camera maker's required card rating for your chosen recording mode.
The computer sees the card, but the camera will not use it
The camera may need a different file system, or it may not support that card type or capacity. Use the camera's format option only after confirming the card is empty, and check the camera manual for supported SD card types. A computer formatting the card successfully does not prove that the camera can use it.
The test stops, or files fail to save or play back
Do not trust the card with the only copy of trip photos. Reseat it, check the adapter's lock switch, and repeat the test with another reader if possible. If the camera still reports errors or cannot play back files, replace the card before you leave.
How to fix a card that does not work
- Reseat the card and adapter. Remove the card, check for dust or visible damage, and insert it firmly. If you use an SD adapter, check its lock switch and try another adapter if available.
- Try another USB port or reader. Connect the reader directly to the computer and avoid hubs or extension cables for the test. A faulty reader can make a good card appear slow or unavailable.
- Close other file transfers. Stop copying files to or from the card while testing. Other transfers compete for the same connection and can make results harder to compare.
- Format the empty card in the camera. Formatting removes all files, so copy anything important first. Use the camera's own format command, then take and play back another photo and video clip.
- Check the camera's card requirements. Look up the supported card type and capacity, plus the speed rating required for the video mode you want. A card can fit the slot but still be unsupported or too slow for a particular mode.
- Test the card in another device. If it fails in more than one reader or camera, the card is the likely problem. If it works elsewhere, check the original reader or camera instead.
When the card may be faulty
Repeated test failures, files that will not open, or recording errors across more than one device are good reasons not to take a chance. Return or replace a new card while you still can. Do not use a card that has failed a read-back or recording check for the only copy of important travel photos.
Speed is not the same as capacity
The USB & SD Speed Test measures transfer speed, not whether every gigabyte printed on the card is genuinely available. It also cannot certify the card's long-term reliability. For a trip, combine the speed check with a camera recording and playback test, and keep a second copy of important photos on another device or storage location.
