How to use an external SSD as a boot drive

If you’re considering upgrading to a Crucial X9 Pro or Crucial X10 Pro
Portable SSD, you may wonder, “Can I use an external SSD as a boot drive?” We have good news. Yes, you can boot from an external SSD on a PC or Mac.

While there may be a list of reasons one might want to use an SSD as a boot drive, the speed that an external SSD offers is usually at the top. Many find that their systems boot faster when they switch from a traditional hard drive (HDD) to an SSD. With an external SSD, you can add in the ease of operation — no need to get out a screwdriver or open your PC case! Instead, with easy plug-and-play USB connections, external SSDs are a cinch to work with.

Here are some common questions we get about booting from an external SSD:

A boot drive is a storage medium with all the crucial files to start and run your computer device. This means that if you want to set up your external SSD as a boot drive, you must load it with your computer’s operating system (for example, macOS or Windows). If you choose an external SSD as a boot drive, keep in mind that your PC or Mac will not turn on (specifically, boot up) without the external SSD plugged in.

A hard disk drive (HDD) uses spinning disk technology to store data, while an SSD uses flash technology that’s faster, quieter, and lighter. While both can be used as a boot drive, a durable SSD is a more reliable, high-performing storage solution. With an SSD, your system will boot faster.

It’s recommended that you have at least 32GB available for your boot drive. However, 64GB could be more optimal for some of the newer operating systems available.

Depending on the model, Macs can be difficult to upgrade. Older iMacs or Mac Mini systems likely came with a hard disk drive — which are much slower than SSDs — or a low-capacity SSD. External SSDs like those in the Crucial portfolio, offer an easy way to increase speed and capacity without replacing internal parts since they connect to your Mac with a plug-and-play USB interface. 

After learning how to install your Crucial external SSD, you’ll find that setting it up as a boot drive is a simple and reliable way to upgrade your system without using a screwdriver.

Note: Just in case you accidentally delete some files or select the wrong drive, Crucial recommends backing up your files in a secondary location before setting up your external SSD boot drive.

Warning! Before you erase your internal drive, make sure you’ve backed up any files you want to save onto another drive. Erasing your drive will permanently delete all files you’ve saved on it.

To wipe your internal drive and begin the process of saving MacOS to your Crucial portable SSD, go to this Apple.com article, How to reinstall MacOS from MacOS Recovery.

After following Apple’s instructions for opening MacOS Recovery, open Disk Utility.

Select your Crucial portable SSD (for example, “Crucial X9” or “Crucial X10 Pro”) from the list of storage disks on the left-hand column.

Select Erase to remove all existing data from the drive.

When prompted for the new volume name, call it by the operating system and Crucial SSD (for example, “macOS X9” or “macOS X10”). Select the filing system that corresponds to your disk format, either APFS or X Extended (Journaled). Leave the scheme set as GUID partition map.

Close Disk Utility, then select Reinstall macOS.

Follow the macOS installer prompts, selecting the “macOS X9” or “macOS X10” volume as the destination for where to install the new operating system.

If you still have questions about using your Crucial external SSD as a boot drive, consider exploring the resources on our website. Whether you’re installing or optimizing your SSD, Crucial offers clear guidance on how to get the most out of your SSD. Here are a few popular resources to check out:

• SSD FAQ
• SSD firmware and support
• SSD form factors explained
• The business case for SSDs

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