By Lighthead Software
Open the Mac App Store to buy and download apps.
Caffeine is a tiny program that puts an icon in the right side of your menu bar. Click it to prevent your Mac from automatically going to sleep, dimming the screen or starting screen savers. Click it again to go back. Right-click (or ⌘-click) the icon to show the menu.
Important: Caffeine lives in the MENU BAR, and this is where its state is indicated. App Store puts the Caffeine icon in the dock, but you can just remove it if you want to.
Great Free App, but...
This app works great on my iMac; in fact, this was the very first app I downloaded from the Mac App Store. I think it's perfect for watching long videos, etc. It's also easy to turn on and off. This is my only complaint: I wish the coffee cup icon in the menu bar at the top of the screen flashed, was larger, or did something else that draws your attention. A couple times I have forgotten to turn it off, because, really, how often do you glance up at your menu bar? Another issue is that last night I had Caffeine turned on because I was running an online timer for practicing an instrument, and before I went to bed, I put the iMac in sleep mode, unknowing that Caffeine was still running, but still saw the screen turn off. At 4:14 AM today, I woke up and my iMac had seemingly turned itself on. Overall, this app does, well, exactly what it says it does, and the best part is that it's free. The only reason I rated it four stars was because I wished the coffee cup drew more attention (maybe put it in the dock instead?). If this issue gets fixed, then this is definitely a five-star app.
Would have paid for this!
I rarely ever purchase apps, so admitting that I would have paid $0.99 for this app is actually saying a lot! I absolutely love this app!
You don’t need the icon in your dock at the bottom of your screen, but it gives you easier access to preferences. From the desktop icon, you can set which desktops the app controls and whether it should start when you turn on your computer. From either the icon on your desktop or the icon in the bar at the top of your screen, you can set the duration of time it will run (incl. indefinitely) and you can turn the app on/off.
Using the app does not change anything except that your computer will not go to sleep while it is turned on (the coffee cup icon at the top is filled). So it is perfect for late-night study sessions, watching videos, or reading online. I have been using this app for a busy week and have not encountered any problems yet. As simple as this app is, it is one of my favorites. :)
Useful for Keeping Mac Awake
Installation puts a coffee cup in your top menu bar. Click the coffee cup. It turns dark inside. That means, your Mac has caffine in it -- it will stay awake. Click the cup again to put the Mac back in normal mode.
Command-click on the coffee cup. There you will find a menu to learn About caffine, to set Preferences, to set the duration of the no-sleep time, and to Quit caffine.
To remove caffine, quit it first and then delete it. Alternatively, open your System Preferences, go to Accounts, select your login account, select Login Items, click on the caffine application, click on the (-) sign to uninstall it as a start-up application, restart your machine, and then delete the application.
As for having an option to stay awake when you shut your Mac ... I'd much rather have my hard drive securely spun down when moving my laptop and have to reconnect to the WiFi than to crash my hard drive in a carzy attempt to keep the WiFi going while tripping over the carpet. Also, this is an app to keep the screen from sleeping. If you want to prevent your system from sleeping, set the System Preferences that way to start.
I think that just about shuts down all the negatives given here. This is the perfect laptop application for watching videos without worrying about your Mac going to sleep. This is also wonderful for the same reason when you have to use your Mac to make projection presentations (aka PowerPoint talks).