macOS: fix it yourself

These steps cover both kinds of Mac. To see which you have, open the Apple menu and choose About This Mac: it shows either Chip (Apple silicon: M1 and later) or Processor (Intel). Back up with Time Machine first if the Mac still starts.

The Mac is slow

1. Restart. Many Macs go weeks without one.
2. Find what is busy. Open Activity Monitor and sort the CPU and Memory tabs; quit anything using far more than its share.
3. Free up space. System Settings, General, Storage. Keep at least 10 to 15% of the disk free.
4. Trim login items. System Settings, General, Login Items. Remove what you do not need at start-up.
5. Update macOS. System Settings, General, Software Update.

Start in Safe Mode

Safe Mode loads only what macOS needs and checks the start-up disk on the way.

• Apple silicon: shut down. Hold the power button until "Loading startup options" appears. Select your disk, hold Shift, and click Continue in Safe Mode.
• Intel: restart and hold Shift straight away until the login window appears.

If the fault disappears in Safe Mode, a login item or extension is the likely cause. Restart normally and remove recent additions one at a time.

Repair the disk with First Aid

1. Open macOS Recovery. Apple silicon: hold the power button until the start-up options appear, then click Options. Intel: hold Command + R at start-up.
2. Open Disk Utility, choose View, Show All Devices.
3. Select the last volume on the disk and click First Aid. Repeat for each item above it, finishing with the disk itself.

If First Aid reports errors it cannot repair, back up what you can and stop.

Test the hardware with Apple Diagnostics

• Apple silicon: hold the power button until the start-up options appear, then press Command + D.
• Intel: hold D while the Mac starts.

Write down any reference code it shows. It tells a technician where to look.

Start-up settings (Intel Macs only)

Odd behaviour with sound, display resolution or which disk the Mac starts from can be cleared by resetting NVRAM: restart and hold Option + Command + P + R for about 20 seconds. Apple silicon Macs do this themselves; shutting down for 30 seconds is the equivalent.

Reinstall macOS without losing files

In macOS Recovery choose Reinstall macOS. It replaces the system and leaves your files and apps in place. Back up first all the same, and keep the Mac on power until it finishes.

When to stop and call us

• A folder with a question mark at start-up that First Aid cannot fix: the Mac cannot find its disk
• Any liquid spill: switch off at once, unplug the charger, and do not switch on again to test it
• A battery that is swollen or a trackpad that has lifted
• Apple Diagnostics shows a reference code

Tell us what you found. Advice by phone and email is free.