In order to erase a USB drive, some users may just delete files or format it. However, neither simple deletion nor formatting can completely erase files, because many data recovery programs can easily and quickly recover deleted or formatted files. Therefore, computer users need to be careful when discarding or selling USB drives, as a large amount of data involving personal privacy and even company secrets can be found on many recycled used flash drives.

Check Flash (ChkFlsh for short) is a tiny and free app for testing and formatting flash drives, developed by Cherkes Mihail from Ukraine. In addition to surface testing, it also allows to check the speed of reading and writing, edit partition info, save and restore full drive and partition images, save and restore MBR, and perform full drive or partition data erasing.