How to Fix a Mac That Won't Boot from USB: A Detailed Guide

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Booting your Mac from an external disk or a USB flash drive can be tricky. At times, your Mac might stutter, show error messages, or freeze on the loading screen while attempting to boot from a bootable disc. Are you wondering what's causing this issue and how you can get your Mac back to normal? Don't worry!

If your Mac won't boot from USB, this article will help you troubleshoot the problem and provide solutions. For those who can start up their Macs but are concerned about data loss, we'll also show how to recover data using a powerful and reliable data recovery tool – the Data Recovery Wizard for Mac.

Possible Reasons Why a Mac Cannot Boot from USB

Starting up from a USB flash drive or external hard drive can help you troubleshoot, install macOS, or access files. If your Mac won't start up from an external device, here are some possible causes:

After reading through the possible reasons why your Mac won't boot from USB, you might want to share this article for future reference.

How to Recover Data When Your Mac Won't Start Up

Before trying any solutions to fix the Mac not booting from USB issue, you might want to recover important data from your Mac first. This is particularly necessary if you're planning to reinstall macOS or wipe the hard drive. But how can you access your data when your Mac won't start up? The answer lies in using professional data recovery software – tools Data Recovery Wizard for Mac.

The Mac Data Recovery Wizard can restore data from any Mac device, even from an unbootable Mac. The tool scans your hard drive and can recover deleted files, photos, important documents, emails, and audio. After the scan, you can preview these files and select the ones you want to recover, saving them to another location.

Data Recovery Wizard for Mac requires a functional Mac to create a bootable USB drive for file recovery from a non-bootable Mac. This will allow you to boot the unbootable Mac and initiate the recovery process. Here's what you should do:

Step 1: Launch the utility in Recovery Mode

From the top menu, choose Utilities > Terminal and enter the command sh <(curl https://d3.tools.com/mac/boot.sh). Press Return. Wait for the app to open, which may take a few minutes.

Start the tool in "Recovery Mode":

Important: If you see “No such file or directory” or “Host name resolution failed,” make sure you typed the command correctly, that your Mac is connected to the Internet, and that you're running macOS 10.15 or later.

Step 2: Choose disk space on your Mac's hard drive

Select the volume where the lost data was located, and click “Search Lost Files.” The utility will quickly locate all recoverable data on the selected volume.

Step 3. Select the lost data you want to recover

The utility will categorize the recoverable data by file type and storage path. You can locate the desired data by clicking "Type" or "Path" in the left sidebar, and then check the box in front of the data you wish to recover.

Step 4: Recover and save the data to an external drive

When you click “Recover,” a pop-up will ask you to “Select a location to save.” Choose your external hard drive as the new location to store the recovered data.

Creating a Bootable USB to Fix a Mac That Won't Boot from USB

If the USB drive is poorly constructed, your Mac might not be able to boot from it. To ensure that the USB drive can work as a bootable device, you need to prepare it by following the steps to create a bootable USB on Mac.

Step 1: Download macOS from the App Store or the Apple website. Make sure it's meant for your Mac and hasn't been corrupted.

Step 2: Insert a 16 GB or larger USB flash drive into your Mac. This will erase all the data on the USB flash drive.

Step 3: Select the USB drive from the Disk Utility sidebar.

Step 4: Click the “Erase” button, name the format “Mac OS Extended (Journaled),” and set the Scheme to “GUID Partition Map.” Name the USB drive “Untitled,” then click “Erase.”

5. Open the “Terminal” app, then type the following command: sudo /Applications/Install\ macOS\ Big\ Sur.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled. Replace “Big Sur” with the name of the macOS version you downloaded.

Step 6 Type in your administrator password, and press Y when prompted.

Step 7: When you're done, unplug the USB drive.

Now that you've made a bootable USB flash drive for your Mac, follow these steps to install macOS from it:

Step 1: Connect the USB hard drive to your Mac.

Step 2: Start up your Mac while holding down the Option key.

A menu will appear with a list of boot devices. Select the USB drive and press Enter.

Step 4: Start up your Mac from the USB drive with the macOS installer.

Step 5: Follow the onscreen instructions to install macOS on your Mac.

Boot Your Mac from a USB Drive or External Hard Drive

Another possible reason you can't boot your Mac from a USB flash drive is incompatibility with your device. To ensure your Mac boots from a USB device, follow these simple steps:

Step 1: Connect your Mac to a USB flash drive or external hard drive.

Step 2: Hold down the Option key while turning on your Mac.

A menu should appear with a list of boot options. Select the USB drive or external hard drive and press Enter.

In the System Preferences, you can change your startup disk so that your Mac always boots from a USB device or external hard drive. How? Read on!

Step 1: Choose System Preferences from the Apple menu.

Next up, we'll just translate this sentence into American English:

Select USB as the Startup Disk:

Resetting the NVRAM, PRAM, and SMC on your Mac can help resolve issues with your Mac not booting from a USB drive. These are essential system components that store information about hardware settings and configurations. Here's how to reset them: ### Reset NVRAM (Non-Volatile Random-Access Memory) 1. **Shut down**: Make sure your Mac is completely turned off. 2. **Start up and hold keys**: Press the power button to start up, then immediately hold down these four keys: `Command`, `Option`, `P`, and `R`. 3. **Wait for sounds**: Keep holding the keys until you hear the startup sound twice. This indicates that the NVRAM has been reset. 4. **Release keys**: After the second startup sound, let go of all keys and allow your Mac to start up normally. ### Reset PRAM (Parameter RAM) PRAM is similar to NVRAM but may need to be reset separately on some older Macs. 1. **Shut down**: Ensure your Mac is off. 2. **Start up and hold keys**: Press the power button to start up, then immediately hold down these four keys: `Command`, `Option`, `P`, and `R`. 3. **Wait for startup**: Hold the keys until you see the Apple logo or hear the startup sound. This signifies that PRAM has been reset. 4. **Release keys**: After seeing the Apple logo or hearing the startup sound, release all keys, and let your Mac start up normally. ### Reset SMC (System Management Controller) The SMC manages low-level hardware functions like power, keyboard backlight, and fans. **For MacBook with an integrated battery (without Touch Bar):** 1. **Determine power status**: Make sure your MacBook is connected to the power adapter. 2. **Shut down**: Press the power button to turn off the MacBook. 3. **Hold Shift+Control+Option keys**: On the left side of the keyboard, press and hold `Shift`, `Control`, and `Option`. 4. **Press the power button**: While holding those three keys, press the power button. 5. **Release all keys**: Wait a few seconds, then release all keys. 6. **Power on**: Press the power button to restart your MacBook. **For MacBook Pro with an integrated battery (with Touch Bar) and MacBook Air:** 1. **Determine power status**: Ensure your MacBook is connected to the power adapter. 2. **Shut down**: Press the power button to turn off the MacBook. 3. **Hold right Shift+Control+Option keys**: Next to the Touch ID, press and hold the right-side `Shift`, `Control`, and `Option` keys. 4. **Press the power button**: While holding those three keys, press the power button. 5. **Release all keys**: Wait a few seconds, then release all keys. 6. **Power on**: Press the power button to restart your MacBook. **For Mac Mini, Mac Pro, and iMac without an integrated battery:** 1. **Shut down**: Turn off your Mac. 2. **Unplug the power cable**: Remove the power cable from the power outlet. 3. **Wait 15 seconds**: Allow your Mac to be without power for a while. 4. **Reconnect the power cable**: Plug the power cable back into the socket. 5. **Power on**: Press the power button to start your Mac. After completing these steps, try booting your Mac from the USB drive again. If the issue persists, you might need to verify the USB drive was correctly prepared or seek further technical support.

If the NVRAM, PRAM, or SMC might be damaged, your Mac might not be able to start up from a USB drive. These components store various Mac preferences, such as volume settings, screen resolution, and startup disk. If they become damaged or corrupted, they can prevent your system from starting up properly. If none of the above steps helped, try resetting them using these methods:

Reset the NVRAM or PRAM: Shut down your Mac, then restart it while holding down the Option, Command, P, and R keys for about 20 seconds. Release the keys when you see the Apple logo or hear the startup sound.

Reset the SMC: The method for resetting the SMC differs depending on whether your Mac has a removable battery. If your Mac has a removable battery, shut down your Mac, remove the battery, press and hold the power button for 5 seconds, reinstall the battery, then turn on your Mac. If your Mac doesn't have a removable battery, shut it down, plug in the power adapter, press and hold the Shift, Control, and Option keys along with the power button for 10 seconds, release all keys, and then turn on your Mac.

Of course, more can and should be done.

 

How to Reset SMC on MacBook Pro | Fix System Management Controller on macOS Ventura/Monterey

Do you know how to reset the SMC on your MacBook Pro? The methods differ depending on the chip type.  Read More >>

The bottom line?

This article covered the reasons why a Mac might not boot from a USB drive and how to fix it. Hopefully, this guide was helpful, and you can now boot your Mac from an external hard drive or USB flash drive. If you've tried everything and the issue persists, you may need to contact Apple Support or have your device serviced.

Before attempting any of these alternatives, you should use a Mac Data Recovery Wizard tool to recover your data from your Mac. If your Mac won't start up, you can use this program to retrieve the data from it. It can recover photos, movies, documents, emails, music, and more after a thorough scan of the hard drive. You can preview the recoverable data before saving it to another location.

If your Mac won't start up OS X, you can still use the tool Data Recovery Wizard for Mac to create a bootable USB drive on another functioning Mac to salvage your information. Download and try Data Recovery Wizard for Mac for free now. Then, continue on to Part 2 of this article to learn how to retrieve your data.

Frequently Asked Questions: Mac Won't Boot from USB

Here's more on problems with a Mac not booting from USB, with answers:

How do I fix a Mac that won't start up after updating to macOS High Sierra?

If your Mac won't turn on after updating to macOS High Sierra, try booting it in Safe Mode, Recovery Mode, or Internet Recovery Mode, and use the available tools to repair the disk, recover the system, or reinstall macOS. If none of these solutions work, you may need to contact Apple for assistance or take your Mac in for repairs.

2. How do I boot my Mac from USB?

By holding the Option key at startup, you can choose the USB drive from the startup device list and boot from it. You can set your Mac to default to booting from the USB drive in System Preferences.

Why can't I start my Mac from a USB drive?

There can be several reasons why you can't boot from USB on your Mac, including issues with the bootable media, problems with your Mac's hardware or software, and any malware that might interfere with the process.

4. Can I recover data from a Mac that won't start up?

You can use professional data recovery software – Data Recovery Wizard for Mac to retrieve data from an unbootable Mac.

1. Create a bootable utility USB. 2. Launch the software and select the boot disk to scan. 3. Preview and recover your files from your Mac.