When booting, you need to hold down the ALT / Option key on the Mac keyboard while powering on the machine to boot from USB. The consequence of picking the wrong drive are potentially disastrous, such as total and complete data loss from your hard drive. **FINAL WARNING** Make sure that the device used in the dd command above is correct. **WARNING** All data on the USB key will be lost is the file path for the input image file. dev/disk2) not a partition designation (ie. is the device the USB key is assigned to. In the example above the device name is /dev/disk2Īs the root user, use the 'dd' command to write the image to the USB drive. In the example above the device name is /dev/sdb Unmount all volumes on the USB drive by typing the following command: dev/sdb Lexar JumpDrive 15G disk AASNGKKA04EW2GXD dev/sda VMware, VMware_Virtual_S 80G disk Lsblk -p -o NAME,VENDOR,MODEL,SIZE,TYPE,SERIAL Double-check to make sure you have the correct drive. **WARNING** The contents will be overwritten in the next steps.ĭetermine which device the USB drive is assigned as by opening the Terminal and typing the following command.

Insert a USB flash drive into a USB slot. For the free edition of MemTest86, this file is called, memtest86-usb.img Inside the Zip there is a 'disk image' file.

Download the current Memtest86 package as a Zip file from this page.Creating a MemTest86 bootable USB Flash drive in Linux/Mac

Boot usb flash with total commander