How to Fix Uninitialized Disk on Mac and Recover Data from It

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fix uninitialized disk on mac

Does Disk Utility show an unintialized disk on your Mac? A brand-new drive might appear this way the first time you plug it into your Mac, but if this is happening to a drive that was previously in use – it’s a sign of malfunction.

And when your drive malfunctions, any data saved on it is in the danger zone. So act fast. In this article, we’ll show you how to fix and secure your data from an uninitialized disk on Mac.

What Does Initialize Disk Mean?

A brand-new, unused disk may sometimes come as uninitialized. That means it’s a completely blank drive with no partitions and no boot information. To initialize a disk on Mac prepares it for usage as either a system drive or a storage device by setting the partition style and identifying boot partitions (if used as a system drive).

Only once you initialize a hard drive on Mac can you format it with a file system like APFS or HFS+ and use it to boot Mac or store your data. We’ll show you how to initialize your drive in the next section.

However, in the case of used drives that were previously working and only recently showed up as uninitialized, you may be experiencing a drive malfunction. In further sections below, we’ve provided you with a list of fixes and a backup and recovery guide.

How to Initialize a Hard Drive on Mac

To initialize an external hard drive on a Mac is straightforward. Once you connect your uninitialized disk to your computer, macOS should prompt you on its own with a pop-up to begin the process with Disk Utility. However, if it doesn’t, you can launch Disk Utility yourself (Finder > Applications > Utilities).disk utility icon in Finder

On the left sidebar, select your drive. Then, click the Erase button at the top of the window – a new window should pop up.Erase button in disk utility window

Name your drive, select its format (we recommend APFS for a Mac system drive and ExFAT for general storage), and select a scheme. Click OK to begin the formatting process.Erase dialog in Disk Utility

Once your drive is formatted, initialization is complete. You should be able to use it with your Mac to store data or boot macOS.

You can also intialize a disk with Mac Terminal using the diskutil erase command. Make sure you select the correct disk!

How to Fix Drive that Can’t be Initialized

Suppose you have previously used your drive to boot macOS or as a storage device, yet your external hard drive won’t initialize. In that case, your drive may be infected, corrupted, or otherwise logically damaged. Below, we’ve prepared 5 different fixes you can try on your Mac.

Before proceeding, we highly suggest you read (and apply) our backup and recovery section first. While some fixes don’t affect the data on your drive, others do. Don’t worry – we’ll still warn you beforehand.

Fix #1: Restart Your Mac and Reconnect Your Hard Drive

Whenever you connect a drive to your Mac, the operating system has to mount it for it to be accessible to the user. However, there are cases where macOS doesn’t have the resources to execute that process. This may result in errors and the drive not showing up on your Mac.

Restarting your Mac can clear up enough resources for it to mount your drive, and reconnecting your drive will restart the process.

If you have one available, you might want to try connecting your drive to another Mac. This will confirm that your Mac is the problem and it may be a sign that you need to do some house cleaning.

Fix #2: Update Your Mac Drivers

If you haven’t updated macOS in a while, the drivers that are responsible for mounting your drive and allowing you to read and write to it may be outdated too. To update your drivers, you need to update macOS.

To update macOS, launch System Preferences > Software Update.software update button in System preferences window

Fix #3: Run First Aid on Your Drive

Your drive may also appear as uninitialized if it’s logically damaged. For example, it was infected by a virus. Or maybe a power outage caused your Mac to shut down while you were transferring data to and from your drive, resulting in corruption.

Fortunately, Disk Utility provides a First Aid tool that automatically diagnoses and repairs disk errors. There’s a limit to what it can do, but it’s a powerful utility.

To use it, launch Disk Utility (Finder > Applications > Utilities) and select your drive from the left sidebar. Then, click the First Aid button at the top of the window.First aid icon in Disk Utility

When prompted, confirm, then check if your drive shows up properly in Disk Utility and in Finder.

Fix #4: Reinstall MacOS

Reinstalling macOS might be a good idea for some users, especially those with older Macs. Bugs, viruses, or system tweaks (or a combination of them) may have made your operating system unstable, thus affecting the mounting process.

Fortunately, Macs have a built-in recovery system that allows users to reinstall macOS without any additional software or tools. To access it, you need to boot into macOS Recovery.

Reinstalling macOS using this method will keep your data intact.

For Apple Silicon Macs:

Step 1. Shut down your Mac.

Step 2.Press and hold the power button until you see “Loading startup options” onscreen.

Step 3.Select Options and click Continue, then follow the reinstallation wizard.

For Intel-based Macs:

Step 1.Shut down your Mac.

Step 2.Press the power button, then press and hold (Command + R) until you see the recovery system window.

Step 3.Select Reinstall and click Continue, then follow the reinstallation wizard.

Fix #5: Format Your Drive

If none of the above fixes work, your last resort may be to format your drive. Formatting will erase all the data still present on the disk, along with any bugs and viruses hiding in its file system. Fortunately, Disk Utility has a tool for this too.

To use Disk Utility to format your drive, follow the instructions in the How to Initialize a Hard Drive on Mac section of this article.

How to Recover Data from Uninitialized Disk

You can recover an uninitialized hard drive or even an uninitialized internal disk on Mac by retrieving your data directly from its file system using data recovery software. To demonstrate this process, we’ll be using a tool called Disk Drill.

You can technically use any data recovery software you want, but Disk Drill will also allow us to create an image backup of the drive in the same app. We can then use Disk Drill’s data recovery tool to extract data from the backup file instead of from the drive itself – which greatly increases our chances of recovering 100% of the lost data. Most importantly, both tools work even if your drive partition appears greyed out on Disk Utility.

Disk Drill Basic for Mac does not offer free data recovery. However, its Byte-to-byte backup tool is 100% free and you can preview as many files as you want. Free data recovery software exists, but not all of them work with disk images (or have an image backup tool).

Step 1.Download and install Disk Drill.

Step 2.Connect your drive to your Mac and launch Disk Drill (Finder > Applications).Disk Drill icon in Finder

Step 3.Select Byte-to-byte Backup in the left sidebar under the Extra tools section. Click OK let’s do it.Byte-to-byte backup window in Disk Drill

Step 4.Select your drive and click Create backup.drive selection window in Disk Drill

Step 5.In the dialogue box that appears, name your image backup file and save it to a folder on your Mac. Once the backup has been created, return to Disk Drill’s initial window. At this point, you may also safely eject your uninitialized drive.byte backup dialog in Disk Drill

Step 6.Click Storage Devices in the left sidebar under the Data Recovery section and click Attach disk image… near the bottom of the window.Attach disk image option in Disk Drill

Step 7.Locate your image backup, select it, and click Attach to add it to the list of drives.disk image selection in Finder

Step 8.Select backup disk image from the list of drives and click Search for lost data.disk image selection window in Disk Drill

Step 9.Wait for the scan to complete, then click Review found items.scan results in disk drill

Step 10.In this window, you can use the search for specific files by name or extension or you can filter found files by type. You can also preview files by hovering your mouse pointer beside a file name and clicking the eye button that appears.preview window in disk drill

Step 11.Use the boxes in the leftmost column to select the files you want to restore and click Recover. You can restore all your files by not selecting anything and clicking Recover all.file selection window in Disk Drill

Step 12.Choose a location on your Mac where Disk Drill will save the recovered files. Then, click Next to proceed with the recovery.destination folder selection dialog in disk drill

Disk Drill Basic for Mac does not offer free recovery. However, you can preview as many files as you want. Free data recovery software exists, but they all have their own limitations.

Conclusion

Unfortunately, an uninitialized disk due to malfunction is common. Even if you maintain your drives properly, factors out of the user’s control (such as data decay or power outages) can cause it at any time. We encourage you to routinely back up your data using Time Machine and an image backup tool like Disk Drill.

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