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. For example, if you install macOS or Microsoft Windows on a USB drive, your Mac can recognize that drive as a startup disk. This guide provides 2 ways to boot a Mac from a USB flash drive.
Insert the drive in the Mac and start Disk Utility (Utilities folder). Select the drive in the left column. Be sure to select the drive (all the way to the left) not a volume (indented below the drive name). Select the 'Partition' tab.
Requirement
- Flash drive repair free download - Mac Free USB Flash Drive Recovery, Mac Free USB Flash Drive Data Recovery, Free Mac USB Flash Drive Data Recovery, and many more programs.
- Check the USB port you have been connecting your drive to. If the port is damaged the drive won't show on your Mac computer. If you are not so sure of the functionality of the port, do a further evaluation to be sure. One way to evaluate further is to try the drive on another port.
Starting up your Mac from an external disk requires the following:
- Intel-based Mac.
- Bootable USB thumb drive formatted with a GUID partition type and containing an OS X installer or a usable operating system.
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.
Way 1: Boot Mac from USB Drive using Startup Manager
Getting your Mac to load from a USB drive is fairly straightforward. Use the following steps, you can easily set Mac boot from an external drive in Startup Manager, so it'll only boot from USB that one time.
Step 1: Insert the USB boot media into a USB slot.
Step 2: Turn on your Mac (or Restart your Mac if it's already on).
Step 3: Press and hold the Option key immediately after you see the Apple logo. Holding that key gives you access to OS X's Startup Manager. Once the Startup Manager screen appears, release the Option key. The utility will look for any available drives that include bootable content.
Step 4: Using either the pointer or arrow keys on the keyboard, select the USB drive you wish to boot from. Once selected, either hit the Return key or double-click your selection. The machine will start to boot from the USB drive.
Way 2: Set a Mac Boot from USB Drive using Startup Disk
When you use Startup Disk preferences to set Mac boot from an external drive, so it'll boot from that disk until you choose a different one. Here is how: Can you use microsoft 365 on mac.
Step 1: Go to Apple menu > System Preference, then click Startup Disk.
Step 2: Click the locked icon and then enter your administrator password.
Step 3: Select External drive as the startup disk, then restart your Mac.
What to do if your Mac does not boot from the selected drive
If you see a message prompts that your security settings do not allow this Mac to use an external startup disk, check the External Boot setting in Startup Security Utility, and then allow your Mac to use an external startup disk.
Step 1: Open Startup Security Utility.
Turn on your Mac, then press and hold Command (⌘) + R immediately after you see the Apple logo. Your Mac starts up from macOS Recovery. When you see the macOS utility window, choose Utilities > Startup Security Utility from the menu bar. When you're asked to authenticate, click Enter macOS Password, then choose an administrator account and enter its password.
Step 2: Select 'Allow booting from external media'.
If you want to select an external startup disk before restarting your Mac, quit Startup Security Utility, then choose Apple menu > Startup Disk.
Note: If you're using Boot Camp in a dual-boot Windows/OS X environment, you may be unable to boot negatively into supported versions of Microsoft Windows XP, Windows Vista or Windows 10 operating systems installed on external USB hard drive.
Make sure disk has been formatted with a GUID partition type
Intel-based Macs support starting from an external USB storage device's volume that has been formatted with a GUID partition type. If you wish to boot from the drive, it's important to format the partition as 'GUID Partition Table' rather than either of the other two ahead of time when you use that drive as a bootable drive.
Make sure your disk is bootable
Volumes that aren't bootable and don't contain a copy of a valid operating system aren't listed in Startup Disk or Startup Manager. Make sure the external drive you're trying to start from contains a usable operating system.
Summary :
Expecting to see the USB drive on desktop after connecting it to Mac? Mac may disappoint you sometimes: your flash drive may be not detected. Why is this happening? How to fix when USB not showing up on Mac? Find your answers in the following content provided by MiniTool Solution. Besides, it shows you how to troubleshoot when internal hard drive not showing up.
USB Not Showing Up on Mac
Many people are complaining about the same problem on the internet: USB not showing up on Mac (flash drive not showing up Mac, SD card not showing up Mac, or thumb drive not showing up Mac). Most of the time, the flash drives are connected to Mac through USB, but you may be disappointed to find out that Mac won't recognize USB sometimes.
Various solutions are provided for you to fix USB flash drive not recognized error and recover data from the inaccessible flash drive.
Can you fix USB not showing up on Mac? How to find SD card on Mac? Actually, the methods and solutions are similar to hard drive not showing up on Mac.
Data recovery tool for Mac:
Data recovery tool for Windows:
Reason 1: Connection Problem
Connection issue is one of the most important reasons why your USB drive not showing up Mac. The broken cable/port, or insufficient/unstable power supply could make your Mac not recognizing USB. When find your flash drive doesn't appear on Mac after connection, you should first do the following things:
- Check the connections and USB cable.
- Change or reset the USB ports.
- Make sure the power supply is enough.
Reason 2: Improper Finder Preferences Settings
You should go to change the Finder Preferences:
- Open Finder.
- Click Finder and select Preferences.
- Check External disks under both General tab and Sidebar tab.
Reason 3: Errors Detected on USB
Please run First Aid to repair your USB flash drive:
- Open Finder.
- Select Applications.
- Choose Utilities.
- Click Disk Utility.
- Select your USB drive from the left pane.
- Click First Aid at the top of the right pane.
- Choose Run in the confirmation window.
In addition, you can check the USB drive and fix it in Terminal.
Reason 4: Not Supported File System
How to reformat the USB drive to a file system that can be supported:
- Navigate to Disk Utility.
- Select the USB drive.
- Select Erase at the top.
- Choose a proper file system.
- Give it a new name or specify a proper file system (optional).
- Click on the Erase button and wait.
Other possible ways to fix USB not showing up on Mac:
- Check the USB flash drive in System Information.
- Reset SMC (how to the SMC of your Mac?)
- Update macOS and firmware.
- Reinstall or update the USB driver.
- Get professionals to help you.
That's all about how do I get my Mac to recognize my USB.
Internal Hard Drive Not Showing Up Mac
What about hard drive not showing up? Please read this page when external hard drive not showing up on Mac. As for the internal hard not showing up problem, I'll discuss it in 2 situations: Mac can start up and Mac can't start up.
Mac Can Start up
If your Mac can still boot up when the internal hard drive is not showing up, please try the following fixes.
Fix 1: modify Mac settings.
- Go to Finder -> Preferences -> General, and make sure the Hard disks option is checked.
- Go to Finder -> Preferences -> Sidebar, and make sure the Hard disks option is checked.
- Go to Finder -> move your cursor to the Locations section in the left panel. When you see the word 'Show' or 'Hide', please click to change it and then check whether the internal disk appears.
Fix 2: check in Disk Utility.
- Try to mount the internal hard drive manually.
- Run First Aid to repair the internal disk.
Mac Can't Start up
If your Mac doesn't boot up as usual, you won't be able to access the internal disk. In this case, you should follow these fixes to repair.
Mac Install From Usb
Fix 1: repair in macOS recovery mode.
You should boot into the macOS Recovery mode and run First Aid:
Boot Mac Usb Drive
Step 1: Go to Apple menu > System Preference, then click Startup Disk.
Step 2: Click the locked icon and then enter your administrator password.
Step 3: Select External drive as the startup disk, then restart your Mac.
What to do if your Mac does not boot from the selected drive
If you see a message prompts that your security settings do not allow this Mac to use an external startup disk, check the External Boot setting in Startup Security Utility, and then allow your Mac to use an external startup disk.
Step 1: Open Startup Security Utility.
Turn on your Mac, then press and hold Command (⌘) + R immediately after you see the Apple logo. Your Mac starts up from macOS Recovery. When you see the macOS utility window, choose Utilities > Startup Security Utility from the menu bar. When you're asked to authenticate, click Enter macOS Password, then choose an administrator account and enter its password.
Step 2: Select 'Allow booting from external media'.
If you want to select an external startup disk before restarting your Mac, quit Startup Security Utility, then choose Apple menu > Startup Disk.
Note: If you're using Boot Camp in a dual-boot Windows/OS X environment, you may be unable to boot negatively into supported versions of Microsoft Windows XP, Windows Vista or Windows 10 operating systems installed on external USB hard drive.
Make sure disk has been formatted with a GUID partition type
Intel-based Macs support starting from an external USB storage device's volume that has been formatted with a GUID partition type. If you wish to boot from the drive, it's important to format the partition as 'GUID Partition Table' rather than either of the other two ahead of time when you use that drive as a bootable drive.
Make sure your disk is bootable
Volumes that aren't bootable and don't contain a copy of a valid operating system aren't listed in Startup Disk or Startup Manager. Make sure the external drive you're trying to start from contains a usable operating system.
Summary :
Expecting to see the USB drive on desktop after connecting it to Mac? Mac may disappoint you sometimes: your flash drive may be not detected. Why is this happening? How to fix when USB not showing up on Mac? Find your answers in the following content provided by MiniTool Solution. Besides, it shows you how to troubleshoot when internal hard drive not showing up.
USB Not Showing Up on Mac
Many people are complaining about the same problem on the internet: USB not showing up on Mac (flash drive not showing up Mac, SD card not showing up Mac, or thumb drive not showing up Mac). Most of the time, the flash drives are connected to Mac through USB, but you may be disappointed to find out that Mac won't recognize USB sometimes.
Various solutions are provided for you to fix USB flash drive not recognized error and recover data from the inaccessible flash drive.
Can you fix USB not showing up on Mac? How to find SD card on Mac? Actually, the methods and solutions are similar to hard drive not showing up on Mac.
Data recovery tool for Mac:
Data recovery tool for Windows:
Reason 1: Connection Problem
Connection issue is one of the most important reasons why your USB drive not showing up Mac. The broken cable/port, or insufficient/unstable power supply could make your Mac not recognizing USB. When find your flash drive doesn't appear on Mac after connection, you should first do the following things:
- Check the connections and USB cable.
- Change or reset the USB ports.
- Make sure the power supply is enough.
Reason 2: Improper Finder Preferences Settings
You should go to change the Finder Preferences:
- Open Finder.
- Click Finder and select Preferences.
- Check External disks under both General tab and Sidebar tab.
Reason 3: Errors Detected on USB
Please run First Aid to repair your USB flash drive:
- Open Finder.
- Select Applications.
- Choose Utilities.
- Click Disk Utility.
- Select your USB drive from the left pane.
- Click First Aid at the top of the right pane.
- Choose Run in the confirmation window.
In addition, you can check the USB drive and fix it in Terminal.
Reason 4: Not Supported File System
How to reformat the USB drive to a file system that can be supported:
- Navigate to Disk Utility.
- Select the USB drive.
- Select Erase at the top.
- Choose a proper file system.
- Give it a new name or specify a proper file system (optional).
- Click on the Erase button and wait.
Other possible ways to fix USB not showing up on Mac:
- Check the USB flash drive in System Information.
- Reset SMC (how to the SMC of your Mac?)
- Update macOS and firmware.
- Reinstall or update the USB driver.
- Get professionals to help you.
That's all about how do I get my Mac to recognize my USB.
Internal Hard Drive Not Showing Up Mac
What about hard drive not showing up? Please read this page when external hard drive not showing up on Mac. As for the internal hard not showing up problem, I'll discuss it in 2 situations: Mac can start up and Mac can't start up.
Mac Can Start up
If your Mac can still boot up when the internal hard drive is not showing up, please try the following fixes.
Fix 1: modify Mac settings.
- Go to Finder -> Preferences -> General, and make sure the Hard disks option is checked.
- Go to Finder -> Preferences -> Sidebar, and make sure the Hard disks option is checked.
- Go to Finder -> move your cursor to the Locations section in the left panel. When you see the word 'Show' or 'Hide', please click to change it and then check whether the internal disk appears.
Fix 2: check in Disk Utility.
- Try to mount the internal hard drive manually.
- Run First Aid to repair the internal disk.
Mac Can't Start up
If your Mac doesn't boot up as usual, you won't be able to access the internal disk. In this case, you should follow these fixes to repair.
Mac Install From Usb
Fix 1: repair in macOS recovery mode.
You should boot into the macOS Recovery mode and run First Aid:
Boot Mac Usb Drive
- Press and hold Command+Option+R Release these keys when an Apple logo or spinning globe appears.
- Choose Disk Utility from the menu.
- Select the internal hard drive from the left panel.
- Click First Aid and wait for the repair process to end.
Fix 2: check in Terminal.
You can use terminal to check the internal hard drive, especially the internal Fusion drive since it is split into an extra SSD and a hard drive. This kind of drive is invisible to users unless you check it in Terminal.
Mac Fix Usb Drivers
Please note:
Stellar Data Recovery for Mac is also useful if you want to recover data from an unbootable Mac. Here's how to recover data from the corrupted internal hard disk on Windows.