Temporarily Prevent a Mac from Sleeping
For security reasons, it’s always a good idea to lock your Mac screen when you step away from the keyboard. On the other hand, there are times where you’ll be away from your Mac but you don’t want to have to re-enter your password to login, or you just don’t want your screensaver activating or your Mac sleeping.
Here’s three ways to temporarily prevent Mac OS X from sleeping or activating the screensaver:
1: Caffeine
Caffeine is a free menu bar utility that is available through the Mac App Store, it sits in your menubar and when you click on the cup of coffee, it prevents your Mac from going to sleep for a preset amount of time: from indefinitely to 5 minutes. I use Caffeine often and have it set to an hour, this is a really useful app.
- Grab Caffeine from the Mac App Store (App Store link)
2: pmset
If you don’t want to install another app, you can mimic the effects of Caffeine by using a command line utility called pmset. Launch the Terminal and type:
pmset noidle
This will prevent your Mac from sleeping indefinitely until pmset is no longer running. You can stop pmset from running by hitting Control+C in the same Terminal window. pmset is a power management utility that you can use to set sleep and wake times, but the noidle flag just provides a single use sleep prevention method.
3: Screen Saver Hot Corners
Another option is to set a screen saver Hot Corner from System Preferences > Screen Savers > Hot Corners. Just specify a corner and set it to “Disable Screen Saver” and anytime you slide the mouse into that corner, the screensaver will not enable. This does not prevent the system from sleeping though.
The pmset trick comes from OneThingWell.
lol I just disable sleep manually from my power options then set it back when I’m done
Caffeine rocks I use it every day, by far the easiest way to do this
An alternative to Caffeine is Jiggler: http://www.sticksoftware.com/software/Jiggler.html
[...] works a lot like Caffeine in that it’s activated only when clicked, there’s no other function to the menubar [...]
I just tried pmset noidle and it didn’t work for me. My screen still went black after 15 minutes or so. My company set default energy saver settings and blocked me from changing them because I don’t have admin privileges on my machine. So I can’t force a no-idle from System Preferences at all. I was hoping pmset noidle would work.
You may need root/admin privileges to use pmset in your situation
Hi,
I tried the command line option on my macbook pro retina running lion and mountain lion and on both after 15 minutes the screen goes black. I don’t understand because in energy settings I have set to Never when hooked to the power adapter. So how to prevent the screen to turn off. What i want is to have the screensaver forever..
Thanks
[...] always been able to temporarily prevent a Mac from sleeping by using the pmset noidle command or a hot corner, but with OS X Mountain Lion, Apple has bundled a command line tool dedicated to sleep prevention [...]
“pmset noidle” worked like a charm – thank you!
[...] are plenty of ways to prevent sleep, whether it’s the caffeinate command, the Caffeine menubar item, pmset, or hot corners, but [...]