Install an Internal or External Hard Drive on your Computer

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Install and format a hard drive for use on Windows or Mac
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Adding another hard drive to your PC or Mac is useful if you are running out of storage space. Or, perhaps you want to upgrade from a hard disk drive (HDD) to a faster solid-state drive (SSD). Luckily, installing a second internal or external drive is easy. This wikiHow article teaches you how to add an extra hard drive to your computer.

Quickly Install a Second Hard Drive

  • Install a SATA drive in an empty drive slot or drive bay and attach the SATA cables.
  • Insert an M.2 SSD into the port on your motherboard and screw it down.
  • Format the new internal or external drive in Disk Management (Windows) or Disk Utility (Mac).
Method 1
Method 1 of 5:

Installing an Internal Hard Drive

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  1. 1
    Make sure your computer has space for another internal hard drive. Most desktop computers have space for another hard drive as long as they have an empty drive slot. However, not all laptops, MacBooks, or all-in-one computers are suitable for an extra internal hard drive. Many laptops only have one drive bay. Check the documentation that came with your computer to make sure your computer is suitable for an extra internal hard drive.
    • For most newer Mac models, it is not possible to install a second internal hard drive. However, on some older MacBooks and iMacs, you may be able to replace the optical disc drive with an internal HDD or SSD. You will need to purchase an adapter that will allow a 2.5-inch hard drive to fit in the optical disk drive space. On some iMac models with a Retina display, you may need a specific SSD model. [1]
    • You can still install an external hard drive on both Windows and Mac computers.
    • If you want to upgrade or replace your current hard drive, you will need to clone your current hard drive to the new hard drive. To do so, you will need to purchase an attachment or enclosure that will allow you to connect your new hard drive to your computer using a USB cable. Then you can use cloning software, such as Macrium Reflect, to clone your current hard drive to the new hard drive.
  2. 2
    Figure out what kind of hard drive your computer will take. There are three types of internal hard drive interfaces you can install in your computer. You can check the user’s manual that came with your computer or the manufacturer’s website to see if your motherboard supports an additional hard drive. If you don’t have this information, you will have to open your computer and check if your computer has a drive expansion slot or an M.2 slot on the motherboard. The following are the most common types of hard drives: [2]
    • SATA: SATA is the most common hard drive interface. They generally have a 7-pin data connection port and a 15-pin power connection port right next to each other. SATA connections can be used with older HDDs or newer SSDs. They can be used in laptops or desktop computers. Desktop SATA drives are usually 3.5 inches. Laptop SATA drives are usually 2.5 inches and thinner. [3]
    • M.2: M.2 is the newest generation of SSD. They are very thin and typically fit on a single chip. They are 22mm wide and between 30mm and 110mm long with connector pins on the end. They may have a B, M, or B &M key connector. You can tell which key connector they have by which side the connector pins have a notch. B connector keys will have a notch on the right side. M connector keys will have a notch on the left side. B and M connector keys will have a notch on both sides. Make sure you purchase an M.2 that is the correct length and has the correct key connector for your laptop or motherboard. Check the connector port inside your computer to see which key connector would fit. [4]
    • IDE: IDE is a much older hard drive interface. It’s much less common to see an IDE interface today, as they have much slower data transfer rates. They typically have a data cable connection that has 39 or 40 pins in two rows, along with a power connection that has 4 large pins.
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  3. You should never attempt to alter your computer's internal components while the computer is running, as you may seriously harm both yourself and the computer.
    • Some desktop computers will take a couple of minutes to finish running after unplugging them. If this is the case for your computer, wait until the computer's fans have stopped running before proceeding.
    • Press and hold the power button after unplugging your computer. This will drain any residual power stored in your computer.
    • If you have a laptop with a removable battery, go ahead and remove the battery as well. If the battery is not removable, be careful not to puncture it.
  4. This will prevent accidental static discharge, which can damage your computer’s components. You can ground yourself by wearing anti-static wrist-straps or by touching something metal before working inside your computer.
  5. This process will vary from desktop computer to desktop computer, so consult your computer's manual or online documentation for specific instructions if you don't already know how to open the case. If you are using a laptop, you will generally turn your computer over and remove the bottom panel.
    • You'll usually need a Phillips-head screwdriver for this step.
    • If you are taking apart a laptop, you may need to detach some cables when removing the bottom panel and accessing your drive bay. Be sure to take note of which cables you detached, so that you know where to reattach them when you are done.
    • If you have an older iMac, you will need to remove the screen. To do so, you will need to use a plastic pry tool and suction cups to remove the glass cover. Then you will need to unscrew the LCD screen underneath the cover and detach all the cables attached to it. Be careful when handling the LCD screen.
  6. On a desktop computer, your primary hard drive will be mounted in a rack that's somewhere in the computer's case; there should be a similar, empty rack near the hard drive. This is where your second hard drive will go. On a laptop, look for an additional drive bay. There may be a separate access panel.
    • M.2 drives will usually be inserted directly into your motherboard. Look for a port or interface that matches the connector on the end of the M.2.
  7. The way the hard drive mounts will be different from one computer model to the next. Some computers may have a mounting cage or drive bracket that you will need to mount the drive inside. You may need to secure the hard drive in the mounting cage with screws, or it may be a tool-less mounting cage. On some computers, the hard drive may just slide into place in the mounting frame. [5]
    • To install an M.2 SSD, simply insert the drive into the connector port at a 45-degree angle. Push the other end of the drive down so it lies flat, and use the attached screw to secure it in place. Congratulations! Your new hard drive is installed. That is all you need to do to install an M.2 SSD.
    • On some laptops, the hard drive will just slide into the bay and connect to the connector. There is no need to connect any cables to the drive.
    • If you are replacing the optical drive on a Mac with a hard drive, you will need to detach the ribbons connecting the disc drive and then unscrew and remove the disc drive. Slide the 2.5-inch hard drive into the adapter so that it connects to the connector port, and then screw it into the same place the optical disc drive went. Then attach the cables to the adapter.
  8. 8
    Attach the cables. After your hard drive is securely installed, connect the data cable to the 7-pin connector on the end of the hard drive, then connect the power cable to the 15-pin connector on the back of the hard drive. After that, connect the other end of the SATA cable to the motherboard.
  9. 9
    Close the case or cover. Once the new hard drive is securely attached, you can go ahead and close the computer. If you needed to detach any cables, make sure you reattach them to their proper locations. Then, you can power your computer back on.
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Method 2
Method 2 of 5:

Formatting an Internal Hard Drive on Windows

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  1. Right-click the Start menu, then click Disk Management in the resulting pop-up menu.
  2. This window will usually appear within a few seconds of opening Disk Management.
    • If the "Initialize Disk" window doesn't appear, click the grey "Refresh" button that's above the Layout tab near the top of the window. You can also right-click the disk labeled “Unallocated space” in the chart and click Format .
  3. This will allow Windows to initialize the second hard drive. Once this process completes, you can proceed.
  4. Right-click the second hard drive's name (it will likely be listed as “Unallocated space”), and click New Simple Volume... in the resulting menu, and click Next on every page of the window that pops up. Your hard drive will be set up and made readable by Windows.
    • Once this process completes, you'll be able to access your second hard drive from the This PC app.
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Method 3
Method 3 of 5:

Adding an External Hard Drive on Windows

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  1. You'll generally want to buy an external hard drive that has enough space for you and comes from a reliable manufacturer such as Western Digital or Seagate. [6]
    • When buying an external hard drive, it's often not much more expensive to buy a terabyte (TB) hard drive rather than a 500 gigabyte (GB) one.
    • A one-terabyte hard drive will usually run under $100.
  2. Plug the hard drive's USB cable into one of your computer's USB ports. You will need to plug it into a high-speed USB 3.1 port or a USB-C port.
  3. You can use the keyboard shortcut to open File Explorer, or click the icon that resembles a folder with a blue clip in the taskbar or Windows Start menu. Doing so opens the File Explorer window.
  4. It's on the left side of the window.
  5. Click your external hard drive's name below the "Devices and drives" heading in the middle of the This PC window.
    • The external hard drive's name will usually contain the name of the manufacturer or the model of the hard drive.
  6. It's a tab in the upper-left corner of the window. A toolbar will appear below this tab.
  7. This option is on the left side of the Manage toolbar. Doing so prompts a pop-up window.
    • Reformatting a hard drive will erase all data on the drive. If there is anything on the hard drive you want to keep, be sure to back it up first.
  8. Click the "File System" drop-down box, then click NTFS or exFAT in the resulting drop-down menu.
    • NTFS is useful for Windows-only systems, while exFAT can be used on any computer or device (Macs included). [7]
  9. It's at the bottom of the window.
  10. Doing so confirms your decision and allows Windows to begin formatting the hard drive.
    • Once the external hard drive has been formatted for your computer, you'll be prompted to click OK , at which point you can use the external hard drive as a second hard drive.
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Method 4
Method 4 of 5:

Adding an External Hard Drive on Mac

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  1. You'll generally want to buy an external hard drive that is Mac-compatible and has enough space for you. You can buy external storage directly from Apple .
    • Make sure that your selected hard drive has a Thunderbolt connector (also known as USB-C) since modern Macs don't support USB 3.0 connectors.
    • When buying an external hard drive, it's often not much more expensive to buy a terabyte (TB) hard drive rather than a 500 gigabyte (GB) one.
    • A one-terabyte hard drive will usually run under $100.
    • If you have an older MacBook or iMac, you can replace the optical disc drive with an HDD or SSD. To do so, you will need to purchase an adapter to hold a 2.5-inch SATA drive in place of the optical drive.
  2. Plug the external hard drive's Thunderbolt cable into one of your Mac's USB-C ports. [8]
    • If you bought an external hard drive that has a USB 3.0 connector, you can buy a USB 3.0 to Thunderbolt 4 (or USB-C) adapter.
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Method 5
Method 5 of 5:

Formatting a Hard Drive on Mac

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  1. 1
    Open the Disk Utilities application. You can find it in the Utilities folder in the Applications folder. To find it quickly, click the magnifying glass/spotlight icon at the top of the screen and search for “Disk Utility.” Click the Disk Utility application.
  2. Click the name of your external hard drive on the left side of the window.
    • The external hard drive's name will usually contain the name of the manufacturer or the model of the hard drive.
    • If you don’t see the hard drive listed in the menu to the left, click View at the top, and then click Show all devices .
    • Make sure you are selecting the top level in the hierarchy in the sidebar to the left. Not the drive under it.
  3. 3
    Click the Erase option. It’s the icon that resembles a hard drive with an “x” icon next to it. It’s at the top of the page.
    • Reformatting a hard drive will erase all data on the drive. If there is anything on the hard drive you want to keep, be sure to back it up first.
  4. 4
    Give the hard drive a name. Enter the name you would like to call the drive next to “Name.” Depending on what other options you select, you may need to change the name.
  5. 5
    Select a format. Use the drop-down menu next to format to select a file system format for the hard drive. The format you should choose depends on how you want to use the hard drive. The options are as follows: [9]
    • Apple File System (APFS): Select this option if you are using a newer version of macOS (version 10.13 High Sierra or newer), and you only plan on using your hard drive with your Mac. You can also select “Encrypted” to encrypt the hard drive with a password or “Case Sensitive” to ensure that all files and folders are case sensitive.
    • MacOS Extended (Journaled): Select this option if you are using an older version of macOS (version 10.12 Sierra or earlier) and you only plan on using your hard drive with your Mac. You can also select “Encrypted” to encrypt the hard drive with a password or “Case Sensitive” to ensure that all files and folders are case sensitive.
    • ExFAT: Select this option if your hard drive has more than 32 GB and you plan on using it with other devices, such as a Windows or Linux computer, or a game console, along with your Mac.
    • MS-DOS (FAT): Select this option if your hard drive has under 32 GB and you plan on using it in other devices, such as a Windows or Linux computer or a game console, along with your Mac.
  6. 6
    Select a Scheme. In most cases, you will want to leave “Scheme” as “GUID Partition Map.” This works best for most computers made within the last 20 years or so. If you need your hard drive to work on an old computer, you may want to select Master Boot Record.
  7. 7
    Select a security option (optional). Security options are available on some hard drives. This allows you to select how many times you want it to overwrite the saved data on the hard drive. This shouldn’t be necessary unless you are using a used hard drive. If security options aren’t available in the menu, your hard drive doesn’t support this feature.
  8. It's at the bottom of the window. This will start formatting the drive with the options you selected. Once it is done formatting the drive, you can start using it as storage. [10]
    • On occasion, Disk Utility may fail to format the hard drive on the first attempt. If this happens, just run it again with the same options you selected.
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Expert Q&A

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  • Question
    How do I install multiple hard drives?
    Spike Baron
    Network Engineer & Desktop Support
    Spike Baron is a Network Engineer & Desktop Support Expert based in Los Angeles, California. He is the owner of Spike’s Computer Repair. With over 25 years of working experience in the tech industry, Spike specializes in PC and Mac computer repair, used computer sales, virus removal, data recovery, and hardware and software upgrades. He has worked as an IT Systems expert for numerous companies, including Huntington Health, Blackbox, Honda, and Manufacturers Bank. In his spare time, Spike also builds and restores computers. He has his CompTIA A+ certification for computer service technicians and is a Microsoft Certified Solutions Expert.
    Spike Baron
    Network Engineer & Desktop Support
    Expert Answer
    After you open the casing, slide your new drive into one of the empty hard drive bays and screw it in. Then plug in one of the power plugs from the power supply unit. Plug one end of a SATA cable into the drive and the other into an open port on the motherboard and you're done.
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    Not Helpful 1 Helpful 1
  • Question
    My laptop got stuck on the booting menu. I have tried removing the RAM and putting it back, which didn't work, and now my hard disk cannot be detected. What should I do?
    Community Answer
    It seems like your hard disk is corrupted. You could try formatting the drive, but this would wipe all your data and remove Windows. You can open CMD from the boot menu and do a clean and format to fix the drive. Your other option would be to get a new drive completely.
    Thanks! We're glad this was helpful.
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  • Question
    How do I save files to my external USB drive?
    Community Answer
    As long as the drive is recognized by your system, which it should be through plug and play, you should just be able to plug it in and drag the files to the external drive through your file explorer.
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      Tips

      • External hard drives can be used to house separate operating systems. If you install a second operating system on your external hard drive, be sure to keep it plugged in at all times.
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      • In addition to being more widely used than IDE drives, SATA drives tend to be faster. Their cables also block significantly less airflow than do IDE cables.
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      Warnings

      • Most hard drives are sensitive to Electrostatic Discharge (ESD), so always remember to ground yourself before touching any of your computer's internal components.
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      References

      1. ↑ https://www.youtube.com/watch?v=a6nawcQ4TCo
      2. ↑ https://www.partitionwizard.com/partitionmagic/how-to-install-a-second-hard-drive.html
      3. ↑ https://tripplite.eaton.com/products/sata-cables-and-speeds-compared
      4. ↑ https://www.atpinc.com/blog/what-is-m.2-M-B-BM-key-socket-3
      5. ↑ https://www.pcworld.com/article/535852/how-to-install-a-new-hard-drive-in-your-desktop-pc.html
      6. ↑ https://www.youtube.com/watch?v=N3cW628iOWc
      7. ↑ https://www.coursera.org/articles/exfat-vs-ntfs
      8. ↑ https://support.apple.com/guide/mac-help/connect-storage-devices-mac-mchl027f1d66/mac
      9. ↑ https://support.apple.com/guide/disk-utility/file-system-formats-dsku19ed921c/22.6/
      1. ↑ https://support.apple.com/guide/mac-help/connect-storage-devices-mac-mchl027f1d66/mac

      About This Article

      Article Summary X

      1. Buy a SATA for your PC.
      2. Turn off and unplug the computer.
      3. Open the case.
      4. Ground yourself.
      5. Slide the disk into an empty mounting space.
      6. Attach the drive to the motherboard and power supply.
      7. Reassemble and restart the computer.
      8. Right-click the Start menu and select Disk Management .
      9. Enable the new drive.

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