Where to find sleep settings on macOS Big Sur
On desktop Macs (iMac, Mac Mini, Mac Studio, Mac Pro), go to System Preferences > Energy Saver. You'll find a slider for "Turn display off after" which controls how long your Mac waits before dimming and sleeping.
On MacBooks, go to System Preferences > Battery > Battery/Power Adapter. Laptops have separate settings for battery and power adapter behavior.
What's different about macOS Big Sur
Big Sur introduced the Battery preference pane for laptops, separating it from Energy Saver. It also introduced the 'Optimize video streaming while on battery' option. Sleep settings are otherwise similar to Catalina.
Why changing settings isn't enough
You can set the display timeout to "Never" on macOS Big Sur, but that's a global change. Your Mac won't sleep on its own until you change it back. On a laptop, that means draining your battery if you forget. And if your IT department manages your Mac, these settings may be locked.
Shake It On on macOS Big Sur
Shake It On keeps your Mac awake on macOS Big Sur by moving the mouse at regular intervals. It works regardless of your Energy Saver settings, including on managed Macs where those settings are locked.
17 smart conditions let you control when it runs: a sustained-CPU window for renders, Wi-Fi/SSID match for office vs home, USB device match for backups, VPN connection for corporate work, camera-in-use detection for video calls. Set it up once and it handles the rest.
When you don't want the cursor moving — overnight renders, screen shares, closed-lid desktop setups — switch to Allow display to sleep or Closed-lid mode and the system stays awake via an IOKit power assertion instead.
Save your favorite configurations as Sessions and switch in one tap from the menu bar. Drive Shake It On from Shortcuts, AppleScript, or a shakeiton:// URL.