How to intentionally mess up a Mac?

Question

Inspired by this question: How to mess up a PC running Windows 7?, I'm interested in repairable ways that you could intentionally 'mess up' a Mac computer.

Note from a Mod on the other question, that should also be mentioned here:

If you suggest ways to disable/break the computer, please include information on how to fix whatever it is you're breaking as well, if it is not immediately obvious.

One-liner answers, that fail to explain how they work or what the do, will be converted to comments.

Answer 1

Use Control-Option-Command-8 to invert the screen colors.

Press it again to turn it back, it's somewhere in the options so those that don't know the hotkey have to hunt.

Answer 2

Install MacDefender

Answer 3

If you can enable the root user, the easiest thing to do would be to chown the user folders of every user account, and then use chmod to prevent the original users accessing them. This is reversed easily enough, as the owner should be clear from the name of the user folder.

Answer 4

Add an AppleScript as a log in item with the following content:

tell application "System Events"
    log out
end tell

Then, every time the user logs in, they will be logged out again. Optionally add a (possibly random) delay and/or a humorous/obnoxious message. To get back use of the computer, hold the shift key down while logging in to disable log in items, then remove the log in item.

For a bit of nostalgia, remember doing similar things with a shut down AppleScript and the Startup Items folder on Mac OS?

Answer 5

A quick one I like to do is press cmdctlshift3 to copy a full screen capture, then open Preview and press cmdN and cmdshiftF to open the screen shot in full screen.

Move the floating controls off the screen if it's a newer version of Preview, and it looks like the computer is frozen.

Pressing esc will exit the full screen view.

Answer 6

Move (or delete) the /System/Library/Fonts folder. Need to use the Console from the CD (or Super User mode) to move the files back. Allows you to log on, but you can't do anything as there is NO text

Answer 7

Change the keyboard layout to DVORAK or similar. Change the login keyboard layout to DVORAK without a warning notification.

Answer 8

Open the /etc/hosts file, and add entries like

127.0.0.1   google.com

Substitute google.com for any legit site. To reverse, remove the line. You need to reboot for changes to take effect

Answer 9

Go to accessibility, and enable two things, one called "slow keys" and one called "mouse keys" There should be a slider for slow keys. Move it up to longest. Slow keys makes it so you have to hold down the key for longer for it to take effect. Mouse keys disables the letter keys. The combination of these two makes it almost impossible to type. Also, greyscale their computer and move the contrast bar up to maximum. It makes their computer look like a messed up cartoon. Glad to be of service! EDIT: Another fun thing is to set a time to make the computer auto shut down. It's somewhere in system preferences. Energy saver maybe?