Over many years there has been countless fake flash memory USB thumb drives sold on eBay. My feeling is that many buyers are completely unaware that what they bought was in fact not only counterfeit but generally has only a small percentage of its stated capacity. I can only presume that most buyers ultimately find these drives fail but put it down to bad luck. Most have left positive feedback before they realise they were duped.
The scam is worldwide & millions of these fakes are sold each year. A brief explanation is, any computer drive has an index called a FAT (File Allocation Table) which is much like a book’s index. The trick performed by these scammers is to electrically reprogrammed this index thus making it report incorrect details when interrogated.
One drive I recently bought had a stated capacity of 128GB but was in reality just 4GB. The problem arises when you exceed the actual physical memory (in this case 4GB). You are tricked into believing that your data was written but instead only the file names were. The data in reality loops, overwriting the physical memory. It isn’t until you attempt to read the data that you encounter a problem. A small amount will be there but most isn’t!
Often if you delve too deeply, such as running diagnostics, or formatting the device it becomes unusable & is no longer able to be read or formatted. I have set up a web page in the hope that it may help other “victims”. The page has an excellent free utility download link that will ascertain whether any USB drive (or memory card) is what it claims to be.
I will over time try to improve this site so that it contains more or better information. It has a feedback link if anyone has any suggestions or feedback.
A quick check would seem that eBay do not like non eBay links so hopefully I am allowed to "type" it as figpond dot com