TL;DR
To repair your Mac startup disk:
- Boot your Mac into Recovery Mode.
- Select your startup disk.
- Run First Aid using Disk Utility on each disk, container, and volume.
Tried and Tested ✅: The methods and steps mentioned in this article have been tried and tested firsthand by Ojash Yadav on his MacBook Pro M3 and rechecked for errors on Hashir’s MacBook Air M2.
Ignoring disk issues can lead to bigger problems. I learned this the hard way, but I figured out how to fix my Mac, and I’m here to help you do the same. In this guide, I’ll show you how to back up your data, use Disk Utility, and easily fix common errors.
How to Repair Your Mac Startup Disk With Disk Utility
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Here is the detailed step-by-step guide to repairing your Mac Startup Disk with Disk Utility:
Depending on your Mac startup disk health, set aside enough time for this task – around five minutes for healthy disks and up to two hours for damaged or corrupted ones.
Step 1: Back Up Your Data Before Repairing Your Disk
Before repairing your disk, back up your files to avoid data loss. Here are some ways to back up your data on Mac:
- Time Machine: Built-in macOS tool for easy backups and file restoration.
- iCloud: Apple’s cloud storage for secure file backups.
- External Hard Drive: Manually copy files by dragging them to a connected drive.
Step 2: Boot Your Mac Into Recovery Mode
To repair the startup disk on your Mac, you must first boot it into Recovery Mode. That’s because the startup disk cannot be repaired while it is being used by macOS. Follow the steps to boot your Mac into Recovery Mode for your respective Mac model below:
The steps for booting your Mac into Recovery Mode differ for Apple Silicon and Intel-based Macs. If you’re unsure about your Mac’s processor, check the Apple Support Page.
On Apple Silicon Mac
To initiate Recovery Mode on an Apple Silicon Mac, follow these steps:
- Shut down your Mac and wait for it to power off fully.
- Press the Power button to restart your Mac.
- Keep holding down the Power button until the startup options page appears. Select Options.
- If prompted, provide your administrator password to log in to your user account.
On Intel-Based Mac
To initiate Recovery Mode on an Intel-powered Mac, follow these steps:
- Shut down your Mac and wait for it to power off fully.
- Press the Power button to start up your Mac.
- Immediately press and hold the Command ⌘ + R keys.
- Keep holding both keys until the macOS Recovery screen appears.
- If prompted, provide your administrator password to log in to your user account.
Step 3: Select Your Disk and Run First Aid
Now that you have booted your Mac into Recovery Mode, you can start repairing your disk. Here’s how to do it:
- Click Disk Utility on the macOS Recovery screen and tap Continue.
- Click the View icon in the top left corner and select Show All Devices from the drop-down menu.
- In the left-hand sidebar, you’ll see all connected disks, containers, and volumes on your Mac in a nested form. The order is Disk > Container > Volume, with each level nested inside the previous one.
- Select the volume, container, or disk you want to repair from the sidebar. Start with the bottom volume and work your way up before moving to the containers and the disk.
- Click the First Aid button at the top of Disk Utility.
- Click Run on the pop-up window. You may be asked to enter your administrator password.
- Wait for First Aid to complete, and then click Done. Repeat these steps for the next volume, container, or disk.
- After repairing all of the disks on your Mac, go to Apple > Restart from the menu bar and restart your Mac.
What to Do After Running First Aid on Your Startup Disk
- If Disk Utility says your disk is fine or repaired, you’re all set. You can click Show Details for more information about the repair.
- If you see overlapped extent allocation errors, it means some files use the same space on your disk, which can cause problems. Look for these files in your disk’s DamagedFiles folder and try to replace or recreate them. If they’re important, open them to ensure they’re still working properly.
- If Disk Utility can’t fix the disk, try repairing it again. If it still fails, back up your data, reformat the disk, reinstall macOS, and restore your files from the backup.
- If the disk problems continue or the disk can’t be repaired, it might be physically damaged. In that case, consider getting the disk repaired or replaced.
Fix Disk Errors With Disk Utility on Mac
Keeping your Mac’s startup disk healthy is essential for your system to function properly. If you’re experiencing issues with your Mac, repair your startup disk as soon as possible. But if the Disk Utility doesn’t work, there are other ways to fix your Mac:
- Check for updates and update macOS on your Mac.
- You can also update apps on Mac to see if it fixes the issue.
- Sometimes, reinstalling your macOS also resolves the issue. But it will erase your hard drive, so create a data backup before proceeding.