You just bought it. Or maybe you're sitting at a desk in a hotel business center or a library, staring at this sleek, silver slab of aluminum and glass, and you feel a little bit ridiculous. It’s an iMac. It’s beautiful. But for the life of you, you can’t figure out how to turn an iMac on because Apple decided that buttons are apparently offensive to the eyes.
Don't feel bad. Honestly, almost everyone has that "where is it?" moment the first time they sit in front of one. Apple's design philosophy has always leaned toward minimalism, and that means hiding the one thing you actually need to interact with to get the machine started.
Finding the Ghost Button
If you’re looking at the front of the screen, you’re looking in the wrong place. There is nothing there. No tactile clicks, no glowing icons, nothing.
Reach around the back. If you are facing the screen, the power button is located on the bottom-left corner of the rear panel. It’s a small, circular indentation. It doesn't stick out; it’s flush with the casing, which makes it even harder to find by touch if you don't know exactly where your finger is supposed to land.
Just press it once. You don’t need to hold it down like you're trying to perform a ritual. A single, firm press is enough. Usually, you’ll hear the fan kick up or, on older models, that iconic startup chime that sounds like a digital "hello." On the newest M1, M3, or M4 iMacs, it’s a silent affair at first, but the Apple logo will pop up on the screen within a few seconds.
What if it’s a Different Model?
Apple has changed things over the years, though not much. If you are working with an absolute relic—say, an iMac G4 (the one that looks like a desk lamp)—the button is on the back of the white dome base. On the G5 and the early Intel white plastic models, it was still on the back, but the shape was slightly different.
But let’s be real. You’re likely using a "Slim" unibody iMac or the new colorful 24-inch silicon versions.
On the 24-inch M-series iMacs, the button is still in that same bottom-left spot on the back. It feels a bit more like a clicky laptop key than the older, deeper-travel buttons on the Intel models. If you’ve got the 27-inch Intel iMac (the one they stopped making a few years back), the button is exactly the same: back left.
The "It Won't Turn On" Panic
Sometimes you press the button and... nothing. Total silence. Black screen. This is when the heart rate starts to climb.
First, check the power cable. This sounds insulting, I know. But on the newer 24-inch iMacs, the power cable is magnetic. It snaps into place with a satisfying "thunk," but if it's slightly crooked, it won't deliver power. Pull it out and snap it back in. Make sure it's flush. On older models, the "kettle" style plug needs to be pushed in hard—I mean really hard—until the plastic flange of the cord is perfectly flush with the aluminum of the Mac. If you see any of the silver metal of the plug sticking out, it’s not in all the way.
🔗 Read more: Neuralink Elon Musk: What Most People Get Wrong
Is the outlet live? Plug a lamp in. Seriously. You’d be surprised how many "broken" Macs are actually just victims of a tripped circuit breaker or a wall switch that someone flipped off.
The Power Cycle Trick
If you know it has power but it's still playing dead, try a power cycle. Unplug the power cord from the back of the iMac. Now, wait. Count to fifteen. Don't rush it. While it's unplugged, hold down the power button for five seconds. This drains any residual electricity from the capacitors on the logic board. Plug it back in and try the normal power-on press.
This fixes an uncanny amount of "dead" iMacs.
Dealing with the Black Screen of Death
What if the computer turns on—you hear the fan or the chime—but the screen stays black?
This is usually a handshake issue between the hardware and the firmware. If you're on an older Intel-based iMac, you can try the "PRAM/NVRAM reset." You’ll need a wired keyboard for this to work consistently. Turn it on and immediately hold down Command + Option + P + R. Keep holding them until you hear the startup chime a second time.
If you’re on a modern Apple Silicon iMac (M1, M2, M3, M4), that trick doesn't exist anymore. These machines do a self-check every time they boot. If it's not starting, try holding the power button down and keeping it held down. On these newer Macs, this will bring up "Loading startup options." If you see that, the screen works, and your problem is likely a software glitch with macOS rather than a broken computer.
Peripheral Interference
Believe it or not, a crappy USB hub or a dying external hard drive can prevent an iMac from booting. The computer tries to "handshake" with every device plugged into it during the Power-On Self-Test (POST). If a device is sending back garbage data, the iMac might just hang there, confused.
Unplug everything. Everything except the power cord.
No printers, no USB dongles, no external drives. Try to turn it on "naked." If it boots up, you know one of your accessories is the culprit. You can then plug them back in one by one until the machine crashes again to find the "traitor" in your setup.
👉 See also: How to download books for free on kindle without breaking the law
When the Button Itself is Broken
It’s rare, but the physical button can fail. If it feels "mushy" or doesn't click, you might have a hardware failure.
Interestingly, there is a way to turn an iMac on without the button if you can get it to boot just once. In System Settings > Energy Saver (or Battery/Display settings depending on your OS version), there is an option that says "Start up automatically after a power failure."
If you check that box, you can "turn on" your Mac just by plugging it into the wall or flipping the switch on a power strip. It's a great "hack" for people who have their iMacs mounted in VESA brackets or cabinets where reaching the back is a total pain in the neck.
Understanding Sleep vs. Powered Off
Most people don't actually need to know how to turn an iMac on every day because you shouldn't really be turning it off.
Modern Macs are designed to sleep. When you’re done for the day, just let it go to sleep or select "Sleep" from the Apple menu. It uses a negligible amount of electricity—almost none—and it allows the computer to run background maintenance like indexing files or downloading updates.
The only times you really need a full cold boot are:
- After a software update.
- If the system is acting sluggish or "buggy."
- If you aren't going to use it for more than a few days.
- If you're moving the computer to a new location.
Actionable Next Steps for a Healthy Startup
If you've successfully found the button and your iMac is humming along, here is how to make sure it stays that way.
🔗 Read more: Samsung Home Label Kit: Why It's Actually Changing How People Use SmartThings
- Configure Startup Items: Once you're in, go to System Settings > General > Login Items. Remove anything you don't absolutely need. This makes the "turning on" process much faster.
- Check your UPS: If you live in an area with frequent power flickers, buy a small Uninterruptible Power Supply (UPS). iMacs don't have batteries like MacBooks; a split-second power drop will shut them down instantly, which can corrupt your SSD over time.
- Dust the Intakes: While you're back there looking for the button, check the bottom edge of the screen and the area near the stand. If there's dust buildup, give it a quick blast with canned air. Overheating during the startup phase is a common cause of random shutdowns.
- Update macOS: Ensure you are running at least the last two versions of macOS to keep the firmware (the code that tells the button what to do) up to date.
Finding the button is the hardest part. Once you've done it a dozen times, your finger develops the "muscle memory" to find that little circular indent without you even having to stand up or peak around the side. It becomes second nature.