If your Mac mini won't boot into Safe Mode, You need to ensure the following aspects are checked:
① You have followed the correct steps to boot into Safe Mode.
The steps to boot into Safe Mode is different on Intel-based and Apple Silicon Macs. Here's how to do it correctly:
On Intel-based Mac:
- Completely shut down your Mac.
- Press the power button, then immediately press and hold the Shift key until seeing the login window.
- Log in to your Mac. (You may need to log in twice.)
On M1 & M2 Mac:
- Fully shut down your Mac.
- Press and hold the power button until "Loading startup options" shows up.
- Select the startup volume.
- Press and hold the Shift key and click "Continue in Safe Mode."
Be reminded that Safe Mode is slow and your Mac may need a long time to enter it. In fact, some users had to wait for about 30 mins to finally boot into Safe Mode on Mac. Give it some time.
When you are in Safe Mode, you'll find the word "Safe Boot" in the top-right side of the menu bar.
② Your Mac's keyboard is working correctly.
Mac won't boot into Safe Mode if the keyboard isn't working properly. You should check if the Shift key on your keyboard is functioning by pressing it down and checking if clicking any letter capitalize it. If it doesn't work, switch to a working keyboard and retry booting into Safe Mode. Use a wired keyboard if possible.
If you are following the right steps and the keyboard is working, consider reinstalling macOS in Recovery Mode to fix Safe Mode not working. This will give your Mac a fresh operating system but keep your personal files intact.