H2testw - Test Real Capacity and Integrity of USB Flash Drives

H2testw is the industry gold-standard data integrity and fake flash drive verification tool developed by Harald Bögeholz for the German computer magazine c't Magazin. It is a standalone, portable utility designed to test USB flash drives, SD cards, and external hard drives for hardware faults and fraudulent modified firmware claiming fake storage capacities.

Key Features of H2testw:

• Detect Fraudulent & Fake Capacity Media: Exposes scam USB drives and counterfeit SD cards that claim huge capacities (e.g., 1TB or 2TB) but actually hold only a few gigabytes of storage.
• Benchmark Real Read and Write Speeds: Accurately measures average write and read throughput (in MB/s) across the entire test surface.
• Data Integrity Verification: Generates distinct test files (.h2w), fills available space, and reads back each byte to detect data corruption or missing sectors.
• 100% Portable & Lightweight: Tiny footprint under 1MB, runs directly without installation or administrator rights required.

How to use H2testw to test your flash drive:

1. Connect your USB drive or memory card to your PC (backing up existing files and performing a quick format is recommended for full capacity tests).
2. Launch h2testw.exe and switch the interface language to English.
3. Click Select target and choose your target drive letter.
4. Under Data volume select all available space, then click Write + Verify.
5. Once finished, if you see \"Test finished without errors\" your media is genuine. If it reports \"DATA LOST\", the drive is defective or counterfeit.