A stick that says 2 TB is not always a 2 TB stick. Counterfeit flash drives and memory cards ship with firmware that reports a size the hardware does not have. macOS believes it, files copy without an error, and the data quietly lands nowhere or on top of something you saved earlier. You find out months later, when the photos will not open.
Drive Capacity Tester writes across the whole drive and reads all of it back. Every position gets a pattern derived from its own offset, so a drive that keeps only a fraction of what it accepts cannot pass by handing the same block back twice.
• The real size, not the printed one
If the drive stores less than it claims, the app reports how much of it is genuine, so you know what you actually bought.
• It stops as soon as it knows
After each file the very first block is read again. The moment that has been overwritten, the drive has wrapped around on itself, and the test ends there instead of running for hours to tell you the same thing.
• Every byte is checked
Verification reads each file back in full and compares it byte for byte, starting with the last file written, where a fake gives itself away first.
• Know the wait before you start
The drive is measured first, so the dialog tells you how long the run will take before you commit to it.
• Nothing is guessed
The block size is measured on the drive in front of you, so a tired SD card and a fast SSD are each written the way that suits them.
Premium features
• Split a long test into sessions
Large drives take hours. Stop when you need the Mac back, continue later, and the files already written are reused instead of written a second time.
• Test several drives at once
Every stick in the drawer in a single run.
• Choose the algorithm and the size
Write only, verify only, or both, over as much of the drive as you want to spend time on.
Please note: testing a drive erases it. Everything on the volume is deleted before the test starts, so copy anything you want to keep somewhere else first.
The app icon was designed by Hugo Santos. You can find more information about my app icons here:
https://sascha-simon.com/icons/
You can find more great apps on my homepage:
https://www.sascha-simon.com
If you enjoy using this app, please leave a positive review. Positive reviews help other users discover the app and are a source of inspiration for me to further develop the app.
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Works, but the free version is annoying
Rustmouse
The product does exactly what it's supposed to do, but if you have a bigger drive and it's bad, it's gonna take forever to test it with the free version. As you get to the bad parts, the speed slows down and the overall test time increases exponentially.But that's what you get if you want to stick to the 'free' version. Don't click in the active test window, or it wll cancel the test that's running - that's something the devloper could fix - make it clear that doing so will stop the test.Other than that - if you're like me, just wanting to confirm the card you have is no good - the free version works fine. If you want more, buy the program.
It ALWAYS fails part way thru, then demands money for Pro in order to continue
geogrety
SCAM APP. If you click, it will cancel hours of work. It NEVER finishes. Then, to continue, you have to pay or START FROM SCRATCH. Absolute grift. Report this app.
Developer Response
Please contact the support. I will try to understand why the test fails. And I forbid you to call this app a scam. It has a free version that works as intended. if there are any errors, you can always contact the support. If you want additional features, you can unlock the Pro version. If you think that this is a scam, I would suggest that you read the definition of a scam.
• Redesigned Pro shop window.
• Redesigned Other Apps window.
Version 5.1.0
The developer, Sascha Simon, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Privacy practices may vary, for example, based on the features you use or your age. Learn More
Accessibility
The developer indicated that this app doesn’t support certain accessibility features. Learn More about the accessibility features.
Information
Seller
Sascha Simon
Size
4.2 MB
Category
Utilities
Compatibility
Requires macOS 15.6 or later and a Mac with Apple M1 chip or later.
Mac Requires macOS 15.6 or later and a Mac with Apple M1 chip or later.
