Use Single-User Mode To Solve Wonky Mac OS X Issues [OS X Tips]

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fsck

I saw this tip over at OS X Daily today, and it reminded me of all the times I did this as a Mac IT guy a couple of jobs back.

See, every so often, the Macs where I worked would start to act weird. Nothing truly game-stopping — just little things, stuff that was easily worked around but always a little bit annoying. The first stop when things are weird, for me, was always Repair Permissions in the Disk Utility app. I’d usually then Verify the disk in that very same app, and see if it returned any errors. If not, I’d usually drop into single-user mode and do a file system check.

Here’s how to do just that.

Be sure to use a wired keyboard if trying this on a Mac desktop machine; I’ve had varying success booting a Mac into single-user mode with a Bluetooth keyboard, if by varying success you mean “rarely ever.” If you’re on a Macbook Air or Pro, you’re good to go.

Shut down the Mac completely, and wait a couple seconds. Then, hold down the Command and S keys simultaneously while pressing the Power button to start up the Mac. You’ll hear the chime, and then a black screen will appear. Shortly thereafter, a bunch of scary-looking white text will show up. This is single-user mode.

Now, when the text is finished filling the screen, and you get a Terminal-style prompt at the end, simply type:

fsck -yf

The first part of that command, fsck, stands for file system check, and it’s a command that’s been in use on Unix and Linux systems since forever. The two flags immediately after, -y and -f, mean “answer yes to any questions,” and “force the check even if the disk isn’t what you expect,” which seems to be a holdover from when journaling started, but I started down a forum rabbit hole and I’ll leave it to you to research it deeper.

Once you type in the command, hit the Return key and wait for the fsck to finish. You’ll get a note at the end that says your drive is OK, or that it needs fixing. If it needs fixing, run the command again, until you get a notice that your drive appears to be OK. Once that happens, simply type:

reboot

Then hit Return again. Your Mac will restart, and it’s likely that things will start to work better.

In my years of taking care of Macs at an agency level, I always used this little trick when stuff wasn’t working quite right (and even when things weren’t working well at all). If you have a Mac that’s working a bit oddly, give this a try.

Via: OS X Daily

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