What is CHKDSK for Mac? How Can I Check the Disk on Mac?

People familiar with Windows should know that the CHKDSK command is used to fix errors when hard disks, USB drives, or memory cards are damaged, or even the system can't boot. Is there a CHKDSK on Mac? Of course! In this blog, we will introduce it in detail and guide you on how to use it.

Table of contents
What is CHKDSK for Mac?
How to Run CHKDSK on Mac to Repair a Corrupted Disk, USB Drive, or SD Card
How to Use CHKDSK for Mac to Fix the Computer that Won't Boot
What to Do When Mac Check Disk Fails?
Conclusion
FAQs

What is CHKDSK for Mac?

CHKDSK is a command-line disk-checking tool for Windows. People can use different commands to handle different hard drive failures, such as "/F" to repair logical file system errors and "/R" to find bad sectors and recover readable information. So, is there a similar command on Mac? Unfortunately, there is not. But don't worry. First Aid in macOS's Disk Utility can do the same job. It is equivalent to CHKDSK on Mac, which not only has a graphical interface but also can solve the hard drive's directory structure problems, read and write errors, inconsistent storage space usage, etc. This is very useful for users to repair damaged drives without formatting. However, compared with CHKDSK in Windows, it has the following shortcomings:

  1. It can't conduct a deeper scan with detailed configuration, such as evaluating bad clusters on the volume or releasing orphaned cluster chains.
  2. It cannot repair external hard drives with the NTFS file system.

How to Run CHKDSK on Mac to Repair a Corrupted Disk, USB Drive, or SD Card

As we mentioned above, using First Aid in Disk Utility can fix drive problems in many situations. If your system is still bootable, follow these steps to check the disk on a Mac.

  1. Click "Launchpad" in the Dock. It's the second icon from the left to the right.
  2. Click Other > Disk Utility.
  3. Select the problematic hard drive in the sidebar. If it's an external hard drive, connect it to your Mac first. Don't see the disk? Please click the View icon on the left of "Disk Utility" to display all devices.
  4. Click "First Aid" in the top menu on the left side of the Window, then click "Run" in the dialog box.

This will start checking the selected disk for errors. When it is complete, you can click "Show Details" to see what errors your hard drive has (usually, they are displayed in red) and whether they have been repaired.

If you encounter a "Process Failed" prompt or cannot repair a damaged drive, use the following method to run the FSCK command. It can check the hard drive's file system and repair damaged parts. However, it is different from CHKDSK in Windows. You need to use it in single-user mode.

  1. In the "Disk Utility," find and remember the file system and the number of the damaged disk. They are marked as 1 and 2 in the screenshot below. If your hard drive's file system is HFS+, then it should displayed as "Mac OS Extended (Journaled)" in mark 1.
  2. Restart the Mac computer and hold down the "Command + S" keys until white text appears on your screen, and then release the keys.
  3. When you see root#, type "/sbin/fsck_filesystem -fy /dev/harddisk number" and press Enter.
  4. After the repair process, type "reboot" and press Enter to restart your Mac.

How to Use CHKDSK for Mac to Fix the Computer that Won't Boot

When the problem occurs with the startup disk, macOS may not run. At this time, you need to put your Mac in Recovery Mode and then try to fix the error with CHKDSK. Here's how:

  1. Press and hold the power button to shut down your Mac.
  2. Put your Mac in Recovery Mode according to its CPU chip.
    Apple chips: Press and hold the Power button until you see "Loading Startup Options." After that, release it.
    Intel chips: Click the Power button, then press "Command + R" immediately. Release the buttons when you see the Apple logo or spinning globe.
  3. Select "Disk Utility" and use First Aid to check the startup disk.

What to Do When Mac Check Disk Fails?

Like CHKDSK in Windows, "First Aid" in "Disk Utility" may not work when your drive has severe errors. Although it is disappointing, as long as the Mac can recognize it, you can initialize the hard drive to make it work properly.

Note: Before starting with the following steps, please back up the data on this hard drive and external storage device. This will erase all the contents of the disk and reset the file system. If you cannot access it at this moment, use iBeesoft Free Data Recovery for Mac to retrieve the files on the hard drive first.

  1. Open the "Disk Utility" and select the damaged hard drive in the sidebar.
  2. Click "Erase" and then click it again in the pop-up Window to confirm the operation.

Tip: If you want to choose a new file system for this drive but don't know which one is suitable, here is a guide on APFS vs. HFS+ vs. exFAT.

Conclusion

Whether it's a built-in internal disk or an external storage device, damage can cause huge losses. After learning CHKDSK on Mac, how to use it, and remediation solutions, you can make the drive usable again without losing data in most cases. However, in order to prevent the hard drive from having problems again, we suggest that you use hard drives properly, check it with First Aid in Disk Application and back up important files regularly.

FAQs

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