There's a specific kind of frustration that comes from walking back to your desk to find a locked screen and a stalled download. Or a render that stopped halfway because macOS decided you'd gone home.
Here's every option you've got.
Why Computers Sleep in the First Place
Sleep mode saves power. On a laptop running on battery, that makes obvious sense. On a desktop or a plugged-in MacBook sitting on a desk all day, it's mostly just annoying.
The sleep timer runs off idle time — no keyboard, no mouse, nothing happening. Most machines default somewhere between 2 and 10 minutes. Fine for normal use. Not fine when you're waiting on something.
Option 1 — Change the System Settings (Temporarily)
The obvious fix, and the one most people try first. The problem isn't finding the setting — it's remembering to revert it afterwards.
On Mac: System Settings → Lock Screen (Ventura and later) → set "Turn display off on battery when inactive" to Never. On older macOS, it's under Energy Saver. The exact path varies by version, but you're looking for display sleep, not system sleep.
On Windows: Settings → System → Power & Sleep → set both "Screen" and "Sleep" to Never. If you're on a laptop, remember to change this back. Leaving sleep off permanently drains the battery overnight.
The manual toggle-it-back problem is real. People forget. That's usually how you end up with a laptop that's been awake for three days.
Option 2 — Terminal on Mac (No App, No Settings)
Mac has a built-in command that handles this cleanly. Open Terminal and run:
caffeinateLeave the window open and your Mac stays awake. Close it and everything goes back to normal. You can also run it for a specific duration:
caffeinate -t 3600That's one hour (3600 seconds), then it stops on its own. Nothing to install, nothing to revert, no settings changed.
Option 3 — PowerToys Awake on Windows
Microsoft's free PowerToys package includes a module called Awake. It sits in the system tray and keeps the machine awake for a set duration or indefinitely, without touching any power settings.
If you haven't got PowerToys installed, it's worth getting for this alone. The rest of the package is genuinely useful too.
Option 4 — Dedicated Keep-Awake Apps
There are several lightweight apps that do exactly this job and nothing else.
Mac:
- Amphetamine (free, App Store) — menu bar toggle, configurable conditions, can stay awake only when a specific app is running
- KeepingYouAwake (free, open source) — simpler than Amphetamine, just a toggle
- Lungo (paid, App Store) — minimal, clean, sets timed durations
Windows:
- Caffeine for Windows (free) — simulates a keypress every 59 seconds so the system thinks you're at the keyboard
- PowerToys Awake (free, as above)
All of these work by either overriding power settings directly or by simulating input to keep the idle timer from firing.
Option 5 — Tools That Handle Wake Lock and Presence Together
There's a category worth knowing about: tools that combine keep-awake with actual click automation. The distinction matters more than it sounds.
A keep-awake tool stops the screen from locking. But if you're running Slack, Teams, or Discord, those apps have their own activity logic that runs separately from the system sleep timer. A tool that only prevents sleep won't affect your chat status. For that you need clicks inside the application area you choose.
Green Dotter does both. Built-in wake lock keeps the screen alive; controlled mouse clicks in areas you define can help with presence management. Mac and Windows.
Which One Should You Use?
Stopping a screen lock during a download or render: caffeinate in Terminal (Mac) or PowerToys Awake (Windows). Free, instant, no install.
Want a menu bar toggle you can leave there permanently: Amphetamine on Mac, Caffeine for Windows.
Need presence management in Slack or Teams as well: You need click automation on top of wake lock. Green Dotter handles both.
One Last Thing — Battery
If you're keeping a laptop awake for extended periods, plug it in. Screen-on time with active processing is the fastest way through a charge. The tools above add no meaningful overhead themselves, but they do prevent the idle state that would otherwise let the machine power down.
Desktops, obviously, don't have this problem.