Understanding Disk Utility’s ‘First Aid’ option [Mac]

Disk Utility: Just like a medical first aid box, anytime a Mac hard drive is suspected of any faults it has to be diagnosed with the Macs very own doctor i.e. Disk utility. Disk Utility can be found from: Application folder > Utilities folder > Disk Utility.

Disk Utility screenshot

First Aid: Any kind of troubles noticed on Mac hard drives and corresponding volumes has to be verified by the ‘First-Aid’ tab. To elaborate the word ‘hard drive trouble’ here, a user may experience any one of those from below:

  • hard drive errors/volumes errors messages,
  • Mac OS X crashes more repeatedly,
  • abnormal sound or act from the connected hard drives,
  • corruption

First Aid option helps Mac OS X to identify the hard drive (volume) problems through efficient scanning of the each blocks of the hard drive. Depending upon the scale of the problem, many a times Disk utility manages to repair the defect which prevents the drive to get into the clutches of even a bigger threat. Mac OS X experts always recommend to run Disk utility’s First Aid option not only under the circumstances of a hard drive error but in general also. This way, running the First-Aid would timely bring out the smallest of the defect on time and if repaired it will prevent the havoc.

Operations done upon a hard drive are:

  • Verify Disk Permissions,
  • Repair Disk permissions,
  • Verify Disk,
  • Repair Disk.

Coming to the ‘Permissions’ in Mac OS X: Several applications on Mac are installed from .pkg file extensions and when an application is installed from .pkg files then a file with extension .bom is saved in the receipt file. This .bom file is kept in /Library/Receipts/ in Mac OS X v10.5 and earlier. These .bom files are useful as they contain the proper permissions for each file and these should not be deleted from a Mac OS X.

When a user request either for the verify/repair disk permissions, the disk utility analyzes these files having .bom extensions and reviews the lists with the real permissions. On verifying the disk permissions the disk utility reports the difference between the file permissions to the user. And, on selecting repair disk permissions the disk utility corrects them.

Differentiating Disk Repair Permissions from Disk Repair:

To repair the damage done to the permissions, the option Repair Disk Permission is used. On the other hand Repair Disk repairs corruption done to the hard drive. Let say, the repair disk option repairs the Mac OS X start-up disk, partition and the directory structure of the drive/volume.

Guest article written by: Vishal is a part of dedicated team working for data recovery Mac software various Mac utilities.

3 thoughts on “Understanding Disk Utility’s ‘First Aid’ option [Mac]”

  1. The first aid option is a little like the scandisk or chkdsk utility that windows used to ship with. I guess that’ll be the easiest way to explain it. It’s not needed much on Windows anywhere with the newer versions of the NTFS file system, but when FAT ruled the roost, it was indispensable.

  2. Having been a PC user for many years I am very familiar with chkdsk and sfc scan. I have only been a MAC owner for the past 6 months and its nice to know it has a similar kind of facility built in. Thank you for the share

  3. I have always liked how easy it is to use the chkdsk for both mack and pc use. I think with enough knowledge you can fix a lot of problems but people are afraid to try and do it themselves.


Leave a Comment

%d bloggers like this: