The act of transferring electronic mail messages from an email client or webmail interface to a portable storage device, such as a USB drive, allows for offline access and backup. This process typically involves exporting emails in a standardized format, such as .pst for Microsoft Outlook or .mbox for other email clients, and then copying these files to the flash drive. For example, a user might export all emails from their Gmail account to an .mbox file and subsequently copy that file to a flash drive.
Retaining copies of electronic correspondence on external media provides several advantages. It serves as a safeguard against data loss due to hardware failure, software corruption, or accidental deletion from the primary email account. Furthermore, it enables access to important communications even without an internet connection. Archiving email in this manner also aids in complying with record-keeping requirements for legal or regulatory purposes, particularly in professional contexts. The practice of archiving electronic documents dates back to the early days of personal computing, with removable media like floppy disks initially serving this function.