I run mac disk utility. It finish saying my disk is fine.

C'mon. Windows chkdsk takes a while.

Why it's so fast? Does it actually check stuffs chkdsk check?

And what should I do if I want chkdsk kind of check (longer but more thorough)


2 Answers 2


The OS X disk utility checks the HFS+ volume header, and its backup header (located in the last block of the disk). If both match, then the rest of the disk is assumed to be consistent. That's along the lines of quick fsck(8) check. Another quick check for journal consistency is performed if you've set up journaling, and if that also checks ok, then the rest is skipped.

You can always run fsck manually, or - http://www.newosxbook.com/ has a tool called HFSleuth which - while directed at programmer/hacker types - can allow you to do a more thorough check.


Did you run the repair on the disk (the top entry in Disk Utility's sidebar) or volume (the indented entry under the disk)? They check (& repair) different things:

Checking a disk checks the partition map and hidden partitions (like the EFI partition). It does not check the volume data structures (except for encrypted volumes -- for them it does the volume check as well). This normally takes a few seconds.

Checking a volume checks the data structures that keep track of individual files within the volume. On a volume with a large number of files (e.g. an OS X system volume), this can take several minutes.

Generally, when verifying/repairing a disk's integrity, I recommend doing both of these operations. Do the disk first, and if that gets a clean bill of health proceed to checking the volume(s) in it.

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