Reviving a Hard Drive for Use With Your Mac

Put that old drive to use

A hard disk drive

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Reviving a hard drive to use with your Mac is a fairly simple process, although not a short one. In this step-by-step guide, we'll show you how to fix an old hard drive that has been giving you problems.

What You Will Need

  • Utilities: To fix your hard drive you will need Disk Utility, which comes free with any Mac computer. Alternatively, you can use a program like Drive Genius, available from Prosoft Engineering. You don't need both utilities. We tend to use Drive Genius because faster than Disk Utility.
  • A hard drive: To what extent you are able to revive a broken hard drive depends on how bad a state the drive is in. Try not to rely on the drive as your primary storage system, as even if you are able to revive the device there's no guarantee of its longevity. Use it to hold temporary or backup data.
  • A current backup: The process outlined in this guide will erase the drive data, so any data that's currently on the drive needs to be backed up if you want to save it. If the drive is preventing you from backing up the data, you'll need to recover the data before you try to revive the drive. A number of third-party data recovery utilities are available, such as Data Rescue, Techtool Pro, and Disk Warrior.

Install the Drive in an External Enclosure

Reviving a Hard Drive - Install a Drive in an External Enclosure
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Installing the hard drive in an external enclosure allows you to run the drive utilities from the Mac's startup drive. This makes for a faster process and avoids the use of a DVD or other startup device, which you would need if you were trying to revive the Mac's internal startup disk. You can still use this process, but the instructions for booting from another startup drive are not included in this guide.

What Type of Enclosure to Use

Any enclosure that accepts your drive's interface will work fine. Most likely, the drive you're attempting to revive uses an SATA interface. The specific type (SATA I, SATA II, etc.) doesn't matter as long as the enclosure can accommodate the interface. You can connect the enclosure to your Mac using USB, FireWire, eSATA, or Thunderbolt. USB will provide the slowest connection; Thunderbolt, the fastest.

You'll want an external drive dock that lets you plug in a drive without any tools, and without having to open an enclosure. This type of drive dock is intended for temporary usage, and it ensures that the drive does not damage any internal interface components.

A standard enclosure may be a better choice if your drive is meant to function as an external drive connected to your Mac.

Attempt to Mount the Drive

The first step in reviving the hard drive is to determine whether or not it is even a candidate for revival. To do this, you will need to confirm that the drive can respond to and perform basic commands.

First, make sure the drive is powered on and connected to your Mac, then turn on your Mac. The Mac will either a) recognize the drive and appear on the desktop, b) display a warning that the drive is not recognized, or c) not respond to the drive's connection whatsoever.

If your Mac does not respond to the drive connection at all, try shutting down the computer, powering off the external drive, and then restarting in the following order:

  1. Turn on the external drive.

  2. Wait at least a minute for the drive to get up to speed.

  3. Turn on your Mac.

If the drive still does not appear, or if you don't receive the warning message, you can try the following:

  • Shut down the Mac and change the external drive to a different connection.
  • Use a different USB port or change to a different interface, such as from USB to FireWire.
  • Swap out the external for a known good drive, to confirm that the external case is working correctly.

Failing these workarounds, the drive is likely beyond saving.

Erase the Drive

The next step assumes that the drive either appeared on your Mac desktop or you received a warning message stating the drive is not being recognized.

Unplug any other external drives you may have connected to your Mac before proceeding. You don't want to accidentally erase the wrong drive.

  1. Launch Disk Utility, located under Applications > Utilities.

  2. From the list of drives, locate and select the one you are attempting to revive. It will have the drive size and manufacturer's name in the title.

    If you are unsure which drive is which, simply unplug the external drive and see which one disappears from the list. Then plug it back in again to confirm it reappears.

  3. Select the Erase tab.

  4. Make sure the Format drop-down menu is set to macOS Extended (Journaled).

  5. Give the drive a name or use the default name, which is "Untitled."

  6. Select Erase. The drive will be erased and will appear in the Disk Utility list with a formatted partition featuring the name you created above it.

If you receive errors at this point, the chances of the drive successfully completing the revival process are diminished. Drives that fail to erase as instructed are more likely to fail in the next step as well.

Scan for Bad Blocks

This next step will check every location of the drive to determine which sections are writable. The utilities used in the following instructions will mark any section that is unable to be written to or read from as a bad block. This prevents the drive from using these areas later.

Reviving a Hard Drive - Erasing and Scanning for Bad Blocks

All drives, even brand new ones, have bad blocks. Manufacturers expect drives to not only have a few bad blocks but to develop them over time. They plan for this by reserving a few extra blocks of data that the drive can use, essentially swapping a known bad block for a reserved one.

In the first set of instructions we will use Drive Genius, and int eh second we will use Apple Disk Utility.

This is a destructive test and will likely lead to loss of data on the drive being tested.

How to Scan for Bad Blocks With Drive Genius

  1. Quit Disk Utility if it's currently running, and launch Drive Genius, usually located under Applications.

  2. Select the Scan or Physical Check option, depending on which version of Drive Genius you have.

  3. Select the hard drive you're attempting to revive from the list of devices.

  4. Select either the Spare Bad Blocks or Revive damaged areas checkbox, depending on which version of Drive Genius you have.

  5. Select Start.

  6. A prompt will appear warning you that this process can cause data loss. Select Scan.

The scan process will begin. After a few minutes, it will provide an estimate of the time needed. In most cases, this will be anywhere from 90 minutes to 4 or 5 hours, depending on the drive size and the speed of the interface. When complete, Drive Genius will report how many, if any, bad blocks were found and replaced with spares.

If no bad blocks were found, the drive is ready to use. If bad blocks were found, proceed to the section titled Drive Stress Test.

How to Scan for Bad Blocks With Disk Utility

  1. Launch Disk Utility, located under Applications > Utilities.

  2. Select the drive from the list of devices. It will have the drive size and manufacturer's name in the title.

  3. Select the Erase tab.

  4. From the Format drop-down menu, select macOS Extended (Journaled).


  5. Give the drive a name, or use the default name, which is "Untitled."

  6. Select Security Options.


  7. Select the option to overwrite the drive with zeros, then select OK.

  8. Select Erase.

When Disk Utility uses the Zero Out Data option, it will trigger the drive's built-in Spare Bad Blocks function as part of the erasure process. Depending on the size of the drive, this process may take as little as 4-5 hours to as much as 12-24 hours.

Once the erasure is complete, if Disk Utility shows no errors, the drive is ready to use. If errors occurred, you likely will not be able to use the drive.

Drive Stress Test

Reviving a Hard Drive - Drive Stress Test

Now that you have a working drive, you may wish to put it in service right away. If you plan to commit important data to the drive, you may wish to run a stress test.

This is a drive stress test, sometimes referred to as a burn-in. The purpose is to exercise the drive by writing and reading data from as many locations as possible for as much time as you can spare. Any weak spot will reveal itself now rather than down the road.

There are a few ways to perform a stress test, but in all cases, we want the entire volume to be written to and read back. Once again, we will use two different methods.

How to Perform a Stress Test With Drive Genius

  1. Launch Drive Genius, usually located under Applications.

  2. Select the Scan or Physical Check option, depending on which version of Drive Genius you have.

  3. Select the hard drive you are attempting to revive from the list of devices.

  4. Select either the Extended Scan or Extended Check checkbox, depending on the version of Drive Genius you have.

  5. Select Start.

  6. You will receive a prompt warning you that the process can cause data loss. Select Scan.

After a few minutes, Drive Genius will provide an estimate of the time needed. In most cases, this will be anywhere from a day to a week, depending on the drive size and the speed of the drive interface. You can run this test in the background while you use your Mac for other tasks.

When the test is complete, if no errors are listed, you can feel confident that your drive is in good shape and can be used for most activities.

How to Perform a Stress Test With Disk Utility

  1. Launch Disk Utility, located under Applications > Utilities.

  2. Select the drive from the list of devices. It will have the drive size and manufacturer's name in the title.

  3. Select the Erase tab.

  4. Use the Format drop-down menu to select macOS Extended (Journaled).

  5. Give the drive a name, or use the default name, which is "Untitled."

  6. Select Security Options.

  7. Select the option to overwrite the drive with DOE-compliant 3-pass secure erase. Select OK.

  8. Select Erase.

When Disk Utility uses the DOE-compliant 3-pass secure erase, it will write two passes of random data and then a single pass of a known data pattern. This will take anywhere from a day to a week or more, depending on the size of the drive. You can run this stress test in the background while you use your Mac for other activities.

Once the erasure is complete, if Disk Utility shows no errors, you're ready to use the drive knowing it is in great shape.