Booting Mac Without Hard Drive

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by Jenefey AaronUpdated on 2021-06-16 / Update for OS X

You may need to boot up your Mac using an external drive or boot volume once in a while, rather than using a start up disk. Booting with an external disk has a lot of significance. Maybe you want to troubleshoot some problems, repair the disk, do partitions, format the entire disk, update, and install OS X etc. All these are executed perfectly when you use an external boot volume to boot up your Mac. In this article, we are here with the detailed step by step guide on how to boot Mac from external hard drive easily. So, let's get started…

How to Recover Data from External Hard Drive in 3 Ways?

Part 1: How to Boot Mac from USB Drive/CD/DVD

Actually, it is possible to boot Mac from external drive or a hard drive, but there are a few specific requirements needed for your Mac to become eligible for that process.

  • First, you have to have an Intel-Based Mac.
  • Second, the CD or DVD you are using to boot must contain Apple’s Super Drive or if you are using a USB drive then it should be formatted with GUID Partition, and you are also required to install OS X installer. Apple is against booting Mac from an external storage device, because you may install an older version of OS X than the one you were using.

Boot from CD or DVD:

If you want to boot your MacBook/Air/Pro/iMac from an optical media like CD or DVD you need to follow the steps below:

1. Open your Mac or restart the device if you were already using it.

Connect the external drive or device to the Mac Reboot the Mac and after the startup chime hold down the OPTION key during boot until you see the boot selection menu Click the external volume to boot from it You will find that external drives typically are shown with an orange icon, with their interface printed on the icon itself. Step 2 Select the Non-booting Hard Disk/Drive. Select the volume that represents non bootable Hard Disk/Drive connected on the system and then click 'Scanning' button. Step 3 Recover Files from Non-booting Hard Disk/Drive. After the scanning is completed, click 'Recovering' button to get back data from Non-booting Macintosh Hard Disk/Drive.

2. When the startup music is playing press and hold the “C” key from the keyboard.

3. This will start the OS X installer from the CD/DVD on your Mac.

Without the HDD in it it will not run. But when you have a bootable external drive with the OSX on it you can boot from that drive: the CD with the OS on it (for exmaple the grey one that came with your MBP; or if you made a bootable clone before you took the internal HDD out: have an external Disk and use CarbonCopyCloner or SuperDuper to make a bootable clone of your internal HDD. In this article, we will show you 3 different backup methods for your Mac with or without external hard drive. You can pick the one that works best for you. How to Backup Mac with External Hard Drive Backup Mac with Time Machine. Mac system has a professional built-in backup tool named 'Time Machine'.

So, it is not too complicated to Mac boot from CD/DVD. You can easily burn a bootable image of OS X on a DVD by using Disk Utility.

Boot from External USB:

Using your USB drive to boot Mac is not as simple as you think. You need to prepare your USB drive beforehand for this specific purpose. You have to format the USB drive and insert the proper Operating System, which is OS X.

1. Turn on your Mac.

2. As soon as the startup music begins you need to press and keep holding the 'Option' key.

3. After that release that key, the Startup manager will be launched.

4. Startup Manager will begin scanning your device and you will be provided with a list of devices that are connected to your Mac.


5. Now, select the drive you want to use with your mouse.

6. Finally, press 'Return' key on the selected option to boot Mac.

This way you can boot your Mac with an external USB drive, but the most critical part is to prepare the USB drive. If you have multiple USB drives connected, then the Startup Manager shall list the drives with the bootable OS. So, this is how to boot Mac from USB drive.

Part 2: Common Problems and Fixes When Boot Mac from External Drive

You may face several issues during MacBook Pro Boot from USB or any external drive. So, a few FAQs are mentioned below which may help you when you are facing any difficulties.

  • 1. Have you tried connecting to a different USB port?
  • If you are unable to startup the installer after connecting the USB drive to your Mac, then first you should try connecting it to a different USB port. It may fix the problem.

  • 2. Have you formatted the USB drive with GUID partition?
  • If you are having problems with your USB storage device then you need to make sure that if you have properly formatted the drive with GUID partition. You have to do it properly otherwise the Intel-Based Mac won't start.

  • 3. Is your Mac shutting down after connecting the disk?
  • Actually, the MacBook contains a preventive measure and because of that computer shuts down automatically when a damaged USB drive is connected or if the USB port itself is damaged.

  • 4. Is your Disk needs repair?
  • If your Mac fails to boot from an external drive even though you have properly installed the OS X installer, then maybe your disk is damaged. You should open Disk Utility and ask permission to repair disk.

  • 5. Have you connected the USB drive properly?
  • There are two types of Apple keyboards, Wired and Wireless. There are also some keyboards with inbuilt USB ports but they may not have enough power to run the drive.

So, this is how to startup Mac from external drive. Follow the frequently asked questions to clear any doubts that you have while booting from external hard drive Mac.

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How To Hard Boot A Mac

Oct 30, 2021 • Filed to: Answer Hard Drive Problems • Proven solutions

If you have to change the device priority list, then you should know how to boot Windows or Mac from the external hard drive. It is the same as choosing an internal drive to be a bootable media. Not every drive can be booted. But by making appropriate changes to the drive boot mechanism, you can make any drive bootable.

The article is all about how to make external hard drive bootable on Windows and Mac computers.The detailed steps are listed clearly for your reference. You can follow to boot the disk.

Reasons for Booting an External Hard Drive

Some people choose to boot their internal hard disk, while others prefer to boot the an external hard drive. The following are reasons why some choose to make their external hard drive bootable.

  1. When Windows 10 fails to boot from the internal hard drive. You need an external bootable hard drive for carrying out a boot mechanism. You can change the priority list from BIOS.
  2. Failure of external media can be due to hard drive corruption, bad sectors, or corrupted partitions containing the BIOS.
  3. Virus or malware attack on the drive containing the BIOS information.
  4. In case you are not able to access your device, you can sue the external bootable media on other devices by using your own operating system anywhere anytime.
What if your Hard Drive Won't Boot in Windows? You can click to learn to solve it.

And before booting up an external hard drive on Windows or Mac, you need to set some essential configurations before carrying out the booting methods.

Setting up Your External Hard Drive

In this section, you would get the solution for booting from an external hard drive. This explains all the essentials for setting up the external hard drive to become bootable media.

1 Figure out your computer’s BIOS key on Windows.

For setting up the external hard drive to become bootable, the first step is to figure out the BIOS key on Windows. As for the device, for setting into BIOS settings, we usually press and hold F12. But in the case of Windows, here are the steps:

Step 1: Launch the search engine. Be it any search engine e.g. google.


Step 2: In the search box, type the computer’s manufacturer, the name of the model, and the phrase bios key. Click enter to continue.

Step 3: Related to your search, the browser will show up with certain options. Select the BIOS key that is compatible with your device.

Step 4: Else you can check the device’s manual to search for the BIOS key.

2 Attach the external hard drive to your computer.

In order to make an external drive bootable, it should be kept in mind that the drive should be in constant and appropriate connection with the device. Use a USB cable or free USB port to attach the hard drive with the device. The external hard drive carries an indicator light that either blinks or stabilize when in sound connection with the device. For Mac devices, you would need a USB or thunderbolt 3 adapter.

3 Format the hard drive if necessary.

As soon as your external hard drive is in an inappropriate connection with your device, make sure the drive should not carry any extra or non-functional data that would otherwise interfere with the boot mechanism. Moreover, if the hard drive is not compatible with the device i.e. the file format on the drive is not compatible, your device won’t be able to read it. In this regard, you can go for formatting the drive into a compatible file system. NTFS for Windows and Mac OS extended are preferred file systems. An all-rounder i.e. exFAT file system can be used for both, Windows and Mac devices. Once the drive and device are compatible, next you have to reformat your drive according to the data going to be stored in it.

Formating hard drive in a safe mode is very important and essential. If you forget to back up your files and folders and lose all the data accidentally, you can use Wondershare Recoverit to recover all your lost data. Only through three simple steps, your precious files will be back.

4 Make sure you have an item from which to boot.

While in the process to boot the external hard drive. There are some requirements. You need a disc image or ISO file present on the hard drive. Only then you would be able to boot the drive. An empty drive is not bootable. Apart from the ISO (disc image) files, the drive can also carry file history backup for Windows or Time Machine backup in case of Mac that makes the drive eligible for booting.

5 Place the boot file on the external hard drive.

It is not necessary that an external hard drive should itself carry the ISO files to be booted, rather you can drag-drop the ISO files into the external hard drive window. If you are using Windows 10 installation tool for creating bootable media, you can skip this step.

6 Make the external hard drive bootable.

Prior to booting the external hard drive, it is important to at least once view the bootable item. For this, you can sue the command prompt in case of Windows or terminal for the Mac devices. In case, if you care to sing Linux to burn ISO files on the external drive, then the drive would be booted in the process.

Booting from an External Hard Drive on Windows

Every operating system carries its own set of requirements when it comes to boot the external hard drive and then to boot the OS from that external media. So as the case with Windows. This section will tell how to boot from an external hard drive Windows 10. Here are the steps:

Step 1: Start the process by connecting the external hard drive with the device appropriately. Make sure that your device recognizes the external hard drive.

Step 2: In the Windows main menu, click the option of power to restart your device.

Step 3: While your device is in process of restarting, press the BIOS key repeatedly.

Step 4: Your device with a restart in and the BIOS menu will appear on the screen.

Step 5: Select the option of boot order from the list.

Step 6: In the next window, select your hard drive in the boot order list. In some cases, the system only allows the USB attached devices to be recognized in the boot order. So make sure that your drive is only USB storage.

Step 7: Now drag your external hard drive to the top of the list i.e. boot order. Save changes and exit BIOS.

Step 8: Now run any on-screen prompt to open, install, or set the program for the external hard drive. In case you already have an OS installed for the external hard drive, then once you are done with the BIOS setting, the OS will open.

Booting from an External Hard Drive on Mac

Booting from an external hard drive on Mac also has a set of instructions. Below mentioned are some of them, just follow the steps and boot from the external hard drive on Mac.

Step 1: Initiate the process by attaching the external hard drive with your Mac device, make sure the connection is appropriate for that the device could recognize the external hard drive.

Step 2: In Mac main menu, select the option of power, and in the pop up select the option of the restart. Your device will restart.

Step 3: As soon as the screen turns off, press the BIOS key destined for Mac devices. Press and hold the BIOS key until the startup manager window appears on the screen.

Step 4: From the menu, select the external hard drive and confirm your selection. This will mark the external hard drive as the booting media for your operating system.

Step 5: Once the drive is selected, exit the startup manager and follow all the on-screen prompt instructions to open, install, and set up the program. In case you already have the operating system, then as soon as you set the priority setting, the OS will open.

Final Words

Hence, using an internal hard drive for booting the operating system via it is a common practice. Mostly C drive is the partition that carries all the system files and is destined to boot the OS. But at times, when the operating system fails to boot due to any technical or physical issue to hard drive i.e. bad sector, corrupted partition, and physical damage to hard drive during a disaster, or whole hard drive corruption due to any virus or malware attack. All these situations won’t allow the operating system to work and leaves your device in a non-functional state. In this regard, using an external hard drive for booting the operating system on your device is recommended. This article is all about the details of two important questions i.e. how to make an external hard drive bootable and how to boot from the external hard drive. This article further explains the process for booting from an external hard drive on Windows and Mac separately.

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