[Windows] Test USB drives for actual storage capacity with H2testw, because knockoff USB drives lie

“$12 for a 64GB flash drive?! Send me 20!” 

Cheap thumb drives and hard drives off of Ebay and from street vendors can often be of dubious quantity and quality, even if they claim to work when you plug them into your computer. H2testw is a program that one ups their sneaky games by verifying your new drive’s storage space.

What is it and what does it do

H2testw runs through a simple process to determine whether a thumb drive has the capacity it claims to have. It just writes data to the drive until it fills it to the brim, and then verifies the data is still alive. If it still exists, the drive is good. If it’s mysteriously disappeared, you may want to look into getting a new drive.


  • Can determine whether drives lie about their capacity
  • Relatively fast
  • Offered in both German and English


  • Does not automatically delete test files
  • To fully work, requires you to delete all files

Cheap thumbdrives bought on sites like Ebay and at cheap street vendors are often of the type that are not actually of a high storage, but are instead faking it by cycling through as the computer writes to the drive. While evil, this has the potential for being very easy to detect: just fill up the drive and read the data off of it. If it can read it, you’re good–but if it can’t, your drive might be a fake.

When using H2testw, be sure to free up as much space as possible on the drive. The larger amount free, the better H2testw will be at detecting the fake drives. After starting, it begins a 5-10 minute process in which it simply writes data to the drives. At the end of the process, it reads it back. If the data matches up, the drive is indeed legitimate, but if it doesn’t, the drive is either losing data or counterfeit.

The proper appearance of an H2testw window is shown to the right. You’ll notice that, while I had only around two thirds of my space free, the entire test passed without errors. This is a strong indication my drive is indeed legitimate.

Conclusion and download link

Ebay users around the world know that you need to be 100% sure of the quality of the goods you’re buying. If you bought a USB drive and think you might have been scammed, it’s important to know for certain whether you really were. H2testw is the perfect program for that, and could potentially save you from repeating a possible costly mistake.

Price: Free! 

Version reviewed: v1.4

Supported OS: Windows 2000+

Download size: 213KB

VirusTotal malware scan results: 0/42

Portability: No installation required!

H2testw homepage (German) | Google Translate | Softpedia page

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  • Ha Ha!
    Nobody likes a Spoiler, Janet! :-) :-)
    I remember a gadget years ago that sat on your desktop and after a complex series of actions, entering codes, etc, it would “securely” turn off a computer.

    April Fool’s joke – got squillions of enquiries.

    BUT – it’s always interesting to follow conversations on Linux lists with the JuniorWannabe-Nerds ranting against people wanting ANYTHING automated. ( Good example: new Linux Mint)

    HOWEVER: This art did just solve a problem of mine – a dud thumb drive that faked the read!


  • J.L.

    @Janet: Convenience, like many software these days. If you know the command-line, registry, and other parts of the system, then there’s no point for a lot of programs.

  • DrTszap

    Well, if you bought the fake USB on eBay, you can open a dispute and get your money back under Buyer Protection…

  • Janet


    I would just fill up most of it with eg a movie and the rest with (a folder of) a bunch of small files, and see how many MB of files didn’t get on it.

    But what would one do if you find the cheap USB didn’t have its full capacity? I doubt that a company that sells such an item is going to take it back and refund your money…:-)…..

  • Mike

    @Janet: But I guess, the program here automates filling the drive up “to the brim” to test the total capacity.

  • Janet

    I don’t get it. Can’t you simply copy a large file you already have (like a movie) and see if the copied data is functional on the drive?