For computers set up to be bootable from a USB drive, it is possible to use a flash drive containing a bootable portable operating system to access the files of the computer, even if the computer is password protected. The password can then be changed, or it may be possible to crack the password with a password cracking program and gain full control over the computer. Encrypting files provides considerable protection against this type of attack.
"Nice device for bulky files....I have 2 of these flash drives and it's more convenient for me to store backups of my most important files on 2 of these flash drives than an external drive because it's easier for me to transfer my data files between 3 devices, carry the drive around in my pocket, and the transfers are easy and fast since it's USB 3.0"
Unlike solid-state memory, hard drives are susceptible to damage by shock (e.g., a short fall) and vibration, have limitations on use at high altitude, and although they are shielded by their casings, they are vulnerable when exposed to strong magnetic fields. In terms of overall mass, hard drives are usually larger and heavier than flash drives; however, hard disks sometimes weigh less per unit of storage. Like flash drives, hard disks also suffer from file fragmentation, which can reduce access speed.