If you have purchased a flash drive from an unverified third-party seller, or if a drive is behaving suspiciously (files disappearing, error messages), you likely need to test it.
Select the Scan for Bad Sectors / Counterfeit Test option. For absolute verification, opt for the full read/write test over the quick test. mydisktest v242
Ensure the physical write-protect switch on your SD card adapter is turned off. Alternatively, format the drive to exFAT or NTFS using Windows Disk Management before running the tool again. If you have purchased a flash drive from