Only recent files readable on a USB drive?

You open a USB drive or SD card and find that newer files work, but older photos, videos, or documents will not open. That can happen when a drive reports more capacity than it really has, but file system damage or failing memory can cause similar symptoms.

First, protect any files you can still read. Then check the drive's real capacity with the Fake USB & SD Check. The test writes data across the device and reads it back, so do not run it on the only copy of important files.

Check the drive safely

1. Open the Fake USB & SD Check, but do not start a test on the problem drive yet. It checks capacity by filling storage with test data and reading it back, which can overwrite or damage files on an unreliable drive.
2. Stop saving new files to the drive. Copy every file that still opens to a different, trusted device. Do not move the files, and do not save the backup onto another partition of the same drive.
3. Check that the copied files open from the backup location. Keep the original drive unchanged while you do this. If important files are missing or fail to copy, skip the capacity test and go to the recovery advice below.
4. For a capacity test, use an empty drive or one with a complete, verified backup. Open the tool on a desktop computer in Chrome or Edge, connect the removable drive, and follow the on-screen prompts to select it and run the check. Other browsers may offer a reduced version or no access to the needed features.

If the drive contains the only copy of anything important, do not test, format, or repair it yet. A test is useful for diagnosing the device, but preserving readable data comes first.

What the result means

The test finds a smaller real capacity than the label claims

The drive may be counterfeit or faulty. Some devices report a large capacity even though they have much less usable memory. Once you write beyond the real capacity, later data can overwrite earlier data, so files may appear in the folder but contain damaged or incorrect contents when opened. Stop using the drive for anything you need to keep.

The test finds read-back errors

The test could not reliably read the data it wrote. This points to unreliable storage, a bad connection, a reader problem, or failing memory. It does not prove which part is at fault, and a pass on one run would not make an unreliable drive safe for important files.

The full capacity verifies

The test did not find a capacity mismatch during that run. The problem could still be file system corruption, damage to particular files, or a connection issue. Try another reader or computer without formatting the original drive, and compare whether the same files fail there.

The tool cannot access the drive

Use Chrome or Edge on a computer and check that the browser can access removable storage when prompted. If the drive does not appear, reconnect it or try a different USB port or card reader. Do not grant access to a different drive by mistake.

What to do about the unreadable files

1. Stop writing to the drive. Do not add files, take more photos on the card, or run a capacity test before recovering what matters. Further writes can replace data that might otherwise be recoverable.
2. Copy readable files to another device. Use a separate drive or computer storage, and open a few copies to confirm they work. If a copy fails, leave the original alone and note which files are affected.
3. Try a different reader or computer. A damaged USB port, loose connection, or faulty card reader can interrupt access. Connect the drive directly rather than through a hub, and compare the same files without changing or repairing the source.
4. Do not format or accept a repair prompt. If Windows asks to scan and fix or format the drive, cancel for now. On a Mac, do not use Disk Utility to erase or repair the only copy of the files before you have a backup or recovery plan.
5. Get help if the files matter. Disconnect the drive and contact a data recovery service if important files will not copy or open. Explain that only recent files remain readable and that you have not formatted the device. See what to do first when recovering data from a fake drive.
6. Replace a drive that fails testing. Do not trust it with backups, photos, or other important data, even if it works briefly after reformatting. If it is under warranty, ask the seller or manufacturer about a replacement after you have secured any recoverable files.

Why recent files may be the ones that open

A fake-capacity drive can make its storage look larger than it is. When data exceeds the real capacity, the drive may continue to report that files were saved while overwriting data in memory it has already used. That can leave newer files readable and older ones damaged, though the exact pattern depends on how the drive was written. A folder listing alone does not prove that every file is intact.

There are other possible causes. A damaged file system can lose track of file locations, and failing flash memory can make particular areas unreadable. A card reader or loose connection can also interrupt access. If the same files fail on more than one computer, the problem is more likely to be on the drive or the files themselves.

After recovering what you can, use a capacity test only on an empty or fully backed-up drive. The test can help identify a false capacity, but it cannot restore files that were already overwritten.