How to spot fake SanDisk memory cards (and test a card you already own)

Short answer: if the price looks too good, the card is almost certainly fake. Buy SanDisk cards from a trusted store with a GST invoice, and test any new card’s real capacity with H2testw (Windows) or F3 (Mac) before an important shoot.

Why fakes are a real problem

A counterfeit card is made to report, say, 256 GB, but contains a much smaller chip. Your camera happily records until the real space is full, and then files start corrupting: often the wedding video, the trip highlights or the burst you can’t reshoot. Fake cards are also usually far slower than their label, causing “card too slow” errors in 4K.

Warning signs before you buy

1. Price far below the market. Compare with SanDisk’s official price; a 50–80% discount is a red flag.
2. Unusual capacities or speed claims that SanDisk doesn’t make for that line.
3. Packaging differences: blurry printing, missing holographic label, spelling errors, missing barcode or warranty information.
4. Sellers with no invoice or no warranty support.

How to test a card you already own

1. Capacity test: run H2testw (Windows) or F3 (Mac/Linux) on the empty card. It fills the card with test data and verifies it. Any errors mean the card is fake or faulty.
2. Speed test: copy a large file or use a disk benchmark. A genuine SanDisk Extreme PRO should sustain well above 30 MB/s writes (its V30 rating).
3. In-camera test: record your camera’s highest 4K mode continuously for 10 minutes. A fake card often stops with a “card speed” error.

Which genuine SanDisk card do you need?

See which memory card for 4K for a full explanation.

What we do in store

Every card we sell is genuine with SanDisk’s warranty and a GST invoice. If you’re unsure about a card you bought elsewhere, bring it in and we’ll help you check it.