Putting the flash in flash memory Flash memory chips are called flash because in order to write to it, the memory is loaded, and then a signal is sent to the memory circuitry that says remember this kind of like the flash on a camera. (In all honesty, I dont know if modern flash memory uses this exact technique, but it remains a fairly accurate metaphor for the process.) Once the memory has been flashed, power can be completely removed, and the memory will retain whatever was written to it. The problem is that memory can be flashed in this manner only so many times. Im finding numbers between 10,000 and 100,000 times though as with anything, Im sure that is increasing over time as well. Regardless, there is a limit. When that limit is approached, some portion of the memory may not properly remember what was written to it, resulting in corruption. It may only take a single bit of information to be wrong, or to wear out, for the entire contents of a flash memory chip to be lost. Some flash memory chips, perhaps even most, now also include circuitry to avoid bad bits. That means if a portion of the flash memory finally wears out and goes bad, the chip itself can compensate, and it will look to the user like everything is fine. Another approach is called wear leveling. This spreads the use of flash memory across the entire device, even if youre only writing to the same spot in the same file every single time. But these techniques only last so long and only postpone the inevitable. Now, in your case, youre using USB thumbdrive in perhaps the worst possible way for longevity. Database applications in particular are notorious for writing to the disk a lot as tables, fields, indexes and the like are updated. Even if you dont write to your database, the files may be updated with things like last access information and other administrivia. As a result, the USB drive is still being written to. A lot. With all that writing going on, reaching the failure point of some random bit or bits in the flash memory stick doesnt seem that far fetched. Remember, in the unluckiest case, it might only take one worn-out bit of information to render the entire contents unreadable. Using inexpensive flash memory USB Memory Stick USB Memory Stick The best use of USB thumb drives and other flash memory-based devices is simply copy-to and copy-from. By that I mean copy the information to the thumbdrive to store it, copy it from the thumbdrive to a local hard disk to use it, and then copy it back to the thumb drive to store it. Never run disk-intensive applications directly against files stored on the thumb drive. If you copy to and from even ten times daily, youre looking at three years of usage for the low end of the flash memory lifespan. (Yes, I know thats not exact. In fact, its way more complex than that; factoring in things like the type of file system, FAT or NTFS, the efficiency of the device driver, and even the circuitry on the specific flash memory device but its a good order of magnitude.) You may also note that your application speeds up when you copy your database to the hard disk for use. While reading flash memory is typically quite fast, writing is not. And finally, if you really need external storage, a thumbdrive may simply be the wrong solution to your problem. There are plenty of external hard drives that could do the same job without the write limitations. Or perhaps a networked solution is the way to go. Back up Knowing that inexpensive flash memory-based devices will wear out eventually, theres one other thing you need to make sure to do, and thats to back up. If you keep your only copy of important data on a flash drive you are asking for trouble. It will wear out eventually, and your data will become completely unrecoverable. Remember the golden rule of backing up: If theres only one copy, its not backed up.