01Three questions need different evidence.
Check the reported size, verify written data and verify the supplier's provenance separately. Packaging and a brief speed result cannot answer all three. TF derives from TransFlash, adopted as microSD in 2005; the name does not prove usable capacity or brand authenticity.
| Check | Evidence | Limit |
|---|---|---|
| Computer capacity | Size reported by the system | Does not verify all space |
| Write-and-read test | Data verified within tested space | Does not prove life or authenticity |
| Supplier documents | Order identity and provenance | Match them to the received cards |
02Test an empty card.
Back up important files first. A full-capacity test writes across the card and takes time. Choose a tool with documented behavior, confirm the target drive and save the report. Never write-test the only copy of customer recordings.
- On Windows, download H2testw from the publisher linked below for a write-and-read test.
- Back up data, prepare an empty card and confirm the target drive.
- Select all available space, complete both writing and verification, and wait for both stages to finish.
- Save tested bytes, results and errors with the card ID. On macOS or Linux, follow the official F3 instructions: f3write followed by f3read checks the written data.
03Investigate failures before calling a card counterfeit.
Errors can come from the card, reader, connection or test process. Record the tool, reader, tested space and error message; if safe, repeat with another reader. Unverified capacity justifies holding acceptance, but is not sufficient evidence to accuse a brand.
04Link the result to the purchase.
Keep lot and sample IDs with device-test results. Agree how failed cards will be handled before the next shipment. Clear acceptance tests are more useful than label photos or peak-speed figures alone.
Before accepting the lot
A worksheet for your own records, not a submitted request.