Getting your Mac to load from a USB drive is fairly straightforward. Way 1: Boot Mac from USB flash drive using Startup Manager Let’s see how to boot a Mac from a bootable USB drive and what to do if your Mac doesn’t start up from it.

Bootable USB thumb drive formatted with a GUID partition type and containing an OS X installer or a usable operating system.

Starting up your Mac from an external disk requires the following: This guide provides 2 ways to boot a Mac from a USB flash drive. For example, if you install macOS or Microsoft Windows on a USB drive, your Mac can recognize that drive as a startup disk. Finally, once it's up you can now go to the disk utils to format and install the MAC OS.By default, Mac starts from its built-in hard disk, but a startup disk can be any storage device that contains bootable contents that compatible with your Mac. Insert the Installer USB stick from step 2, and press the option key while the machine starts.7. Reconnect the battery before closing the shell.6. Open the macbook and disconnect the battery while switching out the drive and make sure both adapter and new SSD sit snug.5. Create a High Sierra Installer on a bootable USB stick.4. For your old driver, please do a full backup via Time Machine.3.

Make sure to install the High Sierra on your old drive, so that a newer firmware is installed that can handle NVME.2.

Please use your original SSD to upgrades your macOS before installation.Support M.2 NVME/AHCI SSD such as Samsung 960 EVO, Samsung 970 EVO/PRO (Not support 960 EVO Plus), WD Black, Crucial P1, HP EX920, ADATA SX8200, Intel 600p series NVME SSD and so on.It can't support recovering from internet, important to prepare bootable USB disk driver(M.2 PCIe has no OS systerm inside,it must be erased first).How to use:1.

This M.2 PCIe nVME SSD convert adapter allows to upgrade SSD for 2013-2015 MacBook with large capacity NVME SSD.It is compatible with MacBook Air 11 Inch A1465 & MacBook Air 13 Inch A1466 (Mid 2013-2017), MacBook Pro (Retina) 13 Inch A1502 & 15 Inch A1398 (Late 2013 - Mid 2015), Mac Pro ME253 MD878.Requires macOS 10.13 High Sierra or Later DO NOT compatible with earlier than macOS 10.13 versions.

Macbook boot from usb key