Rufus turns a removable drive into boot media. The user selects an ISO image, chooses the target USB device, and lets Rufus create the partitions and files that a computer needs at startup. It is commonly used for operating-system installers, recovery environments, firmware tools, and live Linux media. Rufus does not copy an ISO as an ordinary file; it rewrites the storage layout so the computer firmware can treat the device as bootable.
The drive gets erased
Starting a write operation repartitions and reformats the selected device. Existing volumes, documents, and hidden recovery areas on that device do not survive. The warning applies to the whole selected drive, not only to the amount of space that the image appears to need.
Rufus hides external USB hard drives by default and normally concentrates on flash drives, memory cards, and virtual drives. This safeguard reduces accidental erasure, but it does not identify the intended USB stick for the user. Two devices with similar capacities can still be confused. Checking the device name, capacity, and drive letter before pressing Start is more reliable than recognising the first item in the list.
Match the firmware
The partition scheme and target system tell Rufus how the computer should start the media. An MBR layout aimed at BIOS follows a different boot path from a GPT layout aimed at UEFI. A modern computer can sometimes support compatibility modes, but creating one mode does not guarantee the other mode will appear in its boot menu.
A correctly written USB can therefore fail before the installer opens. If the computer runs UEFI without a legacy compatibility mode, media prepared only for BIOS may not boot. Secure Boot adds another boundary. Firmware can reject a bootloader whose signing key appears in its revocation database, even though the ISO and USB contain no write error. Rufus can warn about known revoked UEFI bootloaders, but the final decision still depends on the target machine’s firmware policy.
Write or extract
Some hybrid images let Rufus choose between ISO mode and raw image mode. ISO mode extracts files and builds a normal filesystem, which can leave the drive easier to inspect. Raw mode writes the image sector by sector and preserves its exact disk layout. The image publisher’s boot design determines which choice works best.
Persistence is another separate choice for supported live Linux images. A persistent area stores selected changes between boots; it does not turn every live image into a fully installed system. Images that do not support the expected persistence method may ignore the space. Recovery media may also reset changes by design.
Find an ISO
Rufus can use an ISO already stored on the computer. Its Download choice can also retrieve supported operating-system images, but that button appears only when update checks are enabled. The feature obtains a signed script and runs it in memory to find the available image links. Disabling update checks also removes that route, which can look like a missing feature rather than a privacy choice.
An ISO download still needs verification when the publisher supplies a checksum. Rufus can calculate common hashes for the selected image, and the user can compare the result with the publisher’s value. A successful USB write proves that Rufus completed the requested operation; it does not prove that the source image came from the intended publisher.
Restore the USB
After an installation, a USB drive may show a smaller capacity or several unfamiliar partitions. Rufus can return it to ordinary storage by selecting the non-bootable option and formatting the device with a suitable filesystem. This restoration also erases the boot media. Files copied onto the USB after the installation still need removal or backup before that final format.
