How to Change Which Drive Your Computer Starts From

What changing your boot drive means and why you might do it

Your boot drive is the hard drive or solid-state drive (SSD) that your computer reads when it powers on. It contains your operating system — Windows, macOS, or Linux — and all the files needed to start up. Changing your boot drive means telling your computer to start from a different physical drive instead.

Most people change their boot drive for one of three reasons: they've installed a faster SSD and want to move their operating system to it, they're troubleshooting a corrupted system and want to boot from a backup, or they're setting up a dual-boot system where they can choose between two operating systems at startup.

The process itself is straightforward and does not require reinstalling anything. You're straightforward changing the order in which your computer checks its drives when it powers on. The actual steps depend on whether you're using a Windows PC, a Mac, or a Linux machine.

Key Takeaways

You change your boot drive through your computer's BIOS or UEFI settings on Windows, or System Preferences on a Mac, not through Windows or macOS itself.
On a Windows PC, restart your computer and press Delete, F2, or F12 during startup to enter BIOS, then look for a "Boot Order" or "Boot Sequence" menu.
On a Mac, restart and hold Command+Option+R to enter Startup Disk settings, where you can select a different drive from a list.
If your new drive doesn't appear in the boot menu, it may not be recognized by your computer yet — check that it's properly connected and shows up in your system's storage settings first.
You can always change your boot drive back to the original drive using the same method if something goes wrong.

Changing your boot drive on Windows

On a Windows PC, you access boot settings through BIOS (Basic Input/Output System) or UEFI (Unified Extensible Firmware Interface), depending on your computer's age and manufacturer. These are low-level settings that run before Windows itself loads. You cannot change your boot drive from within Windows — you have to restart and enter these settings during startup.

Restart your computer and watch the screen carefully as it powers on. You'll see a brief message telling you which key to press to enter setup or BIOS — common keys are Delete, F2, F10, or F12. The exact key depends on your motherboard manufacturer (Dell, HP, Lenovo, ASUS, etc.). Press that key repeatedly as soon as you see the message. If you miss it, restart and try again.

Once you're in BIOS or UEFI, look for a menu labeled "Boot," "Boot Order," "Boot Sequence," or "Boot Priority." The layout varies widely, but you're looking for a list of drives. Use your arrow keys to move through the menu — the mouse usually doesn't work in BIOS. Move your new drive to the top of the list so it's checked first when your computer starts. Save your changes (usually by pressing F10 or selecting "Save and Exit") and restart.

If you don't see your new drive listed in the boot menu at all, it may not be recognized yet. Shut down, open your computer's case, and double-check that the drive is connected to both a power cable and a data cable (SATA or NVMe, depending on the drive type). Restart and try again. If it still doesn't appear, the drive may be faulty or your motherboard may not support it.

Changing your boot drive on a Mac

On a Mac, the process is simpler because Apple built boot drive selection into the operating system itself. You don't need to enter firmware settings. Restart your Mac and when ready hold down Command+Option+R (or Command+R on older Macs). Keep holding until you see a spinning globe or the macOS Utilities window.

In the Utilities window, click "Startup Disk" in the menu bar at the top. You'll see a list of all drives connected to your Mac. Click the drive you want to boot from, then click "Restart." Your Mac will restart from that drive and remember your choice for future startups.

If your new drive doesn't appear in the Startup Disk list, make sure it's properly connected and formatted as Mac OS Extended or APFS (Apple's newer file system). You can check this by opening Disk Utility while still in the Utilities window. If the drive shows up in Disk Utility but not in Startup Disk, it may not have a valid macOS installation on it yet.

Making sure your new drive is recognized before you change the boot order

Before you enter BIOS or Startup Disk settings, verify that your computer actually sees your new drive. On Windows, open File Explorer and look in "This PC" — your new drive should appear as a separate item in the list. If it doesn't, the drive isn't connected properly or isn't being recognized by your motherboard.

On a Mac, open Disk Utility (Applications > Utilities > Disk Utility) and look for your new drive in the left sidebar. If it's there, it's connected and recognized. If it's not, check the physical connection and restart your Mac.

If your drive shows up in Windows File Explorer or Mac Disk Utility but doesn't appear in your boot menu, the drive may not have a bootable operating system on it yet. You may need to install Windows or macOS on the new drive first, or restore a backup to it, before you can boot from it.

What to do if your computer won't start after changing the boot order

If you change your boot drive and your computer shows an error message or a black screen instead of starting up, the new drive either doesn't have a working operating system on it, or it's not connected properly. Don't panic — you can fix this.

Restart your computer and go back into BIOS or Startup Disk settings using the same method you used before. Move your original drive back to the top of the boot order, save, and restart. Your computer should boot normally from the original drive. Then you can troubleshoot why the new drive didn't work — usually it's a loose cable or a drive that needs an operating system installed on it.

If you can't remember how to get back into BIOS, or if your computer won't respond to the startup key you pressed before, try a different key. Common alternatives are F1, F3, F5, F8, and Escape. If none of those work, look up your specific computer model and "enter BIOS" — the manufacturer's support page will tell you the correct key.

Cloning your operating system to a new drive instead of reinstalling

If you want to move your entire Windows or macOS installation — including all your programs, settings, and files — to a new drive without reinstalling, you can use cloning software. This copies everything from your old drive to your new one, bit by bit.

On Windows, free tools like Macrium Reflect, EaseUS Todo Backup, and AOMEI Backupper can clone your drive. On a Mac, you can use Disk Utility's "Restore" feature or third-party tools like Carbon Copy Cloner or SuperDuper. Most of these tools walk you through the process step by step.

After cloning, your new drive will be an exact copy of your old one. You can then change your boot order to start from the new drive. The advantage is that everything works exactly as it did before — no reinstalling programs or reconfiguring settings. The disadvantage is that cloning takes time (usually 30 minutes to several hours depending on drive size) and requires enough free space on your new drive to hold everything from the old one.

Frequently Asked Questions

Can I have two operating systems and choose which one to boot into?

Yes. This is called dual-booting. You need two separate drives (or two partitions on one drive) with different operating systems installed on each. After you set up both systems, your computer will show a menu at startup asking which one you want to use. The exact setup process depends on which operating systems you're combining — Windows and Linux dual-boots are common, but Windows and macOS on the same machine is not supported by Apple.

Will changing my boot drive erase anything on my old drive?

No. Changing your boot order only tells your computer which drive to read from when it starts. Your old drive stays exactly as it is. You can keep it connected and access its files from your new operating system, or disconnect it and store it as a backup.

What if I don't see a boot menu option in BIOS?

Look for "Boot Order," "Boot Sequence," "Boot Priority," or "First Boot Device." Different manufacturers use different names. If you're still stuck, restart and look for an onscreen message that says "Press [key] for Boot Menu" — that's different from entering BIOS and may give you a simpler list to choose from.

Do I need to unplug my old drive before booting from the new one?

No. You can leave both drives connected. Your computer will boot from whichever drive you put first in the boot order and ignore the others. Some people unplug the old drive just to be certain there's no confusion, but it's not necessary.

How do I know if my new drive is actually faster than my old one?

Check the drive's specifications — look for "read speed" measured in MB/s or GB/s. SSDs are typically much faster than older hard drives (HDDs). You can also run a speed test tool like CrystalDiskInfo on Windows or Disk Diag on a Mac to see real-world performance after you've booted from the new drive.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.