Flash drives now a day are most common and easy way of data transfer, but due to improper use your flash drive may get faulty and may cause issues like it does not format, data you stored disappeared etc.
It could be a case when you have a fake flash drive, we had written an extensive post on how to identify fake flash drives and this tool also will let you whether is a fake pen drive which is creating issues for you.
Here goes some description about this tool
H2testw is a simple to use programs which allows you to test USB sticks for various kinds of errors, which occurs with USB Drives. It can also be used for any other storage media like memory cards, internal and external hard drives and even network volumes.
This application can be used to check other storage media like big space data drives, memory cards and even network hard disk partitions.
Note: If the drive you want to test is not empty, it can still test the drive for errors but wont be able to test the complete space on the drive, it will produce a prompt like the one shown above.
It fills the chosen target directory with test data and then reads it back and verifies it. H2testw does not overwrite or erase any existing data.