How to prepare evidence for a counterfeit drive dispute

A USB drive or SD card may claim far more space than it can actually store. If you are preparing a counterfeit storage claim, preserve the purchase details and the drive’s current condition before testing it.

The Fake USB & SD Check writes test data across the drive and reads it back to check its real capacity. Because this test writes to the storage, do not run it on a drive that contains files you need to keep.

Prepare and run a capacity test

1. Record the original evidence first. Photograph the drive, label, packaging, seals, and any printed capacity or model details. Save the original product listing, receipt, order number, and seller messages. Do this before testing or changing anything.
2. Open the test on a computer. Use Chrome or Edge on a computer. The Fake USB & SD Check has limited or no access in other browsers. Keep the drive disconnected until you are ready to test it.
3. Make sure the drive is empty. Copy off files you need and verify that the copies open. For a dispute, consider whether testing could change or destroy material you may need as evidence. If it could, stop and ask the seller, your payment provider, or a qualified technician how to proceed before writing to the drive.
4. Select the correct drive and run the check. Connect the USB drive or card reader. Follow the browser’s file picker to give the test access to the drive, then run the fill-and-read-back capacity check. Confirm the selected drive by its name and capacity, and do not use a drive with important data on it.
5. Save the result and test details. Capture the result as it appears, along with the date, the advertised capacity, the computer and browser used, and any errors or interruptions. Keep the original screenshot or photo unedited, and make a separate copy if you need to mark it up for your records.

Keep the drive, packaging, and any included adapter together after the test. Do not format, repartition, or run repair utilities on the drive while you are documenting a dispute.

What the result means

The test reads back less storage than advertised

This is evidence that the drive did not reliably store and return data across its claimed capacity under the test conditions. Some counterfeit drives use a controller that reports a larger size than the memory can actually hold. When data goes beyond the real capacity, it may be lost or overwrite earlier data.

Keep the test result beside the listing that shows the advertised capacity. The result supports a claim about the drive’s usable capacity, but by itself it does not prove who made the drive or whether the seller knew it was counterfeit.

The test completes without finding a capacity mismatch

The drive passed this check under the conditions you used. That does not establish that the product is genuine, match every advertised specification, or rule out intermittent faults. Preserve the result anyway, and compare the label, model, packaging, and seller’s description with the original listing.

The test stops, errors, or gives an unclear result

An interruption can come from a loose connection, a card reader, a browser permission issue, or faulty storage. Record what happened, including any error shown, and note whether the drive was disconnected or the computer went to sleep. Do not present an interrupted test as a completed capacity result.

Keep the dispute record clear

1. Keep originals unchanged. Save original photos, screenshots, receipts, and messages. Make copies for highlighting or adding notes, and label those as copies so they are not confused with the originals.
2. Write down the test conditions. Note the computer, operating system, browser, reader or adapter, and the capacity printed on the product or shown in the listing. Include the date and whether the test completed in one run.
3. Match the evidence to the purchase. Include the order number, seller name, purchase date, and the exact listing or product description. Keep messages with the seller in their original form when possible.
4. Describe what you observed, not what you assume. For example, say that the drive was advertised as a certain capacity and that the check read back less data. Avoid claiming that the test proves intent or identifies the manufacturer.
5. Ask what evidence is needed before sending the drive back. A seller or payment provider may ask for photos, a test result, or a return. Keep a copy of the complete record and follow the stated return instructions. Do not mail the only copy of evidence you have.

If the drive already contains important files

Do not run a fill-and-read-back test on it. Writing across the storage can overwrite files, especially on a counterfeit drive whose reported capacity is inaccurate. First preserve the existing contents using a method appropriate to the files and your situation, and keep notes about any copying you do. If the data is valuable or the dispute requires the drive to remain unchanged, get advice before connecting it again.

When to get an independent check

If the seller disputes the result, the test was interrupted, or the contents matter, ask whether an independent technician can inspect the drive without unnecessary changes. A capacity check can show that storage does not behave as claimed, but a technician may be better placed to document the device and test conditions. Keep the packaging and purchase record until the dispute is resolved.