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07 - All about 'Fake' USB flash memory drives

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What is a 'Fake' USB Flash Drive (UFD)?

Many USB flash drives are being sold on eBay and other auction sites at very cheap prices (too cheap!). These USB pens are usually of a high capacity (8GB, 16GB, 32GB, 64GB or 128GB) and usually from the Far East, but some UK sellers also sell these too. 98% of these sellers are selling 'fake' USB Flash drives (fake UFDs) - either knowingly, unknowingly or I-don't-really-want-to-know-ingly!
If you buy one of these fake UFDs they will appear to work fine and Windows will show them at their 'rated' capacity - for instance a 64GB UFD will appear in Windows to have a capacity of say 61.3GB, you may even give the seller positive feedback. However, these UFDs actually only contain about 2GB of real memory. When you start putting your files onto it, everything may appear to be fine - until you fill it up with more than 2GB and then it completely corrupts all the files on it! Bet you wish you hadn't paid £40 for it now!

The fake UFD is actually made from a 2GB flash memory chip (and probably 2nd †rate 'reject' memory at that), but it has been programmed to falsely report it's capacity as 64GB.

Don't be caught by these cheats. Simply ask them to test the UFD using RMPrepUSB or H2TESTW before you buy it. If they refuse then walk away from the deal! Explain to them that if the UFD passes H2TESTW they will get a lot more bids if they state this in their adverts.

Do you have a fake Kingston Flash Drive? One simple way to check is that usually Kingston print text onto the metal USB connector which has the model number and capacity + other numbers. If your Kingston drive has no printing on the connector, it may well be a fake!

How to test a suspect UFD

A good practical test of a USB flash drive is to fill the drive up with jpg photos. Then try looking at the photos to see if they are all accessible and not corrupt. The thumbnail view in Windows Explorer will do this for you quite nicely!

If you have bought a 'bargain' UFD, you can test it using the 'Gold Standard' test H2TESTW written by Harald Bogeholz for c't magazine. This test is very thorough but very slow because it tests all bytes of unused memory (even if it doesn't exist). The test utility is not now included in the RMPrepUSB download but there is a link to the download on the RMPrepUSB help form - just run H2TESTW.exe and select English as the language and the USB drive you want to test. H2TESTW will fill up the UFD with large files but will not destroy any files you already have on the UFD (but it you may lose all the files if the UFD is a fake one). The test can take 4-8 hours to test a good 16GB drive and considerably longer if it is faulty.

A much quicker test is to use the RMPrepUSB Quick Size Test button.†

This test does destroy all data on the UFD and you will need to re-format the drive using RMPrepUSB after testing it. But a 16GB UFD can be †tested in about 6-10 minutees. Note that RMPrepUSB is not a thorough test, but if it fails RMPrepUSB it will fail H2TESTW. If RMPrepUSB Quick Size Test passes, then (if you have the time) you should test it twice with H2TESTW just to make sure the memory is all good quality. If it fails, RMPrepUSB will tell you the approximate true size of memory present in the pen (though the memory may be faulty/unreliable).

If you have a fake UFD, you cannot easily 'repair' them and even if you reformat them to their true capacity using RMPrepUSB, the memory is probably of such poor quality (reject chips sold off by the factory as faulty) that it will sooner or later cause corruption of your most important files. You may not even realise your files are corrupt for months and may even have lost the original files by the time you find out!

To reprogram a fake flash memory drive, you will need to find the manufacturers tool and program it with the correct capacity - for details on how to do this see†Tutorial #39.

For more details about fake UFDs, see SOSFlakeFlash website here.

ATTENTION: If you have a USB Flash Drive that does not seem to work with Windows and
causes the computer to slow up or stop responding
whenever you try to use it or access it -
please read the tutorial #23 here†for instructions on how to fix it.

If your USB Flash drive does not seem to format using RMPrepUSB,
check that Windows has assigned it a drive letter. If not use Drive Manager to add a drive letter to the drive.
The easiest way to access the disk management console is go to Start-Run and enter "diskmgmt.msc"
right-click on the USB drive area and choose 'Change drive letter and paths...' - then add a drive letter.

Keywords: USB, corrupt flash drive, thumb drive, not responding, slow, freeze, hang, stop, access, bad, cheap, fake, pen drive, size, capacity, china, hong kong, taiwan

Updated on Aug 20, 2011 by Steve Si (Version 32)

Attachments (3)

DiskMan.png - on Aug 20, 2011 by Steve Si (Version 1)

Kingston.jpg - on Aug 20, 2011 by Steve Si (Version 2)

quicksizetest.jpg - on Feb 6, 2011 by Steve Si (Version 1)