I would like to monitor the messages generated when I boot my Mac, similar to what you on a *nix box. Is there key-combo to press/hold that will let me do this?

2 Answers 2


You have to press cmd + v upon startup to see the boot output. Press this right after the chime.

If you want to make that permanent, you should probably do something along the lines of:

sudo nvram boot-args="-v"

To undo the above:

sudo nvram boot-args=

in the Terminal. (/Applications/Utilities/Terminal.app)

note: I haven’t tested the above commands, but I’m sure a google query will help you there if you want to make it permanent.

  • 3
    I can hardly wait to try this. I hate staring at the apple on boot.
    – chiggsy
    Commented Nov 24, 2010 at 3:29
  • 1
    Why? What's wrong with it? Commented Feb 12, 2011 at 9:55
  • As a Linux user, I am used to reading log messages during startup. They are far more interesting than a boring progress bar. Now that I've bought my first iMac, I'm pleased to have startup log messages on it too.
    – Christoph
    Commented Apr 8, 2023 at 17:11
  • boot-args allow much more, for instance not sleeping when closing the lid, despite having no external monitor, see: apple.stackexchange.com/a/301847/266584 Commented Jun 5 at 21:16

If you want to see the boot messages after the boot occurred, log in and run sudo dmesg in Terminal.app.

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