If your desktop Mac isn’t switching on or booting, there are a number of things you can try to isolate and resolve the issue. This guide will help you work through the most common causes.
Check the Power Cable and Connections
The most common reason a desktop Mac won’t power on is a loose or faulty power cable. Make sure the cable is securely connected at both ends, your Mac and the power outlet.
For Apple Silicon iMacs, confirm the connection to the external power supply is firm and secure.
If available, test with another Apple-authorised power cable and power outlet to rule out a faulty cable or socket. Always use genuine Apple or certified third-party cables for safety.
Check for signs of damage, wear, or fraying on the power cable. If any are found, stop using the cable and replace it.
Make sure your display is set to the correct input source and watch for any flickering, which could indicate a connection issue.
Perform a Power Cycle
Disconnect the power cable from your Mac for at least 30 seconds. Then reconnect it to both your Mac and the wall outlet, and press the power button to attempt startup again.
Reset the System Management Controller (SMC)
For Intel-based desktop Macs, resetting the SMC can help resolve power issues:
- Unplug the power cable from your Mac.
- Wait around 15 seconds.
- Reconnect the power cable and wait an additional 5 seconds.
- Press the power button to turn on your Mac.
🔎 Note: Apple Silicon Macs do not require an SMC reset. This action is performed automatically when disconnecting and reconnecting power.
Disconnect External Peripherals
Remove all connected devices from your Mac, including USB drives, external displays, hard drives, and audio interfaces. These can occasionally draw too much power or cause conflicts during startup.
Try powering on your Mac with only essential accessories connected, such as a mouse, keyboard, and display.
Try Safe Mode or macOS Recovery
For Intel-based Macs: Press the power button, then immediately hold the Shift key to boot into Safe Mode.
For Apple Silicon Macs: Press and hold the power button until you see “Loading startup options.” From here, you can attempt to boot into macOS Recovery.
