Why is my Mac not accepting my password when I try and change system settings?

If you’ve found yourself fully signed into your Mac (or MacBook) but it just won’t accept your password when you try and change any of your system settings, then this may be due to a fault with your devices security chip.

What security chip?

Modern Macs contain a security chip, named T2. This is used for storage of security information as well as on-the-fly encryption and decryption. If you have a fingerprint reader on your device for example, it’s this chip that stores and processes your fingerprints.

Does my computer have one?

There are 2 ways to find out.

1. Most Mac devices since around 2018 have had one, but Apple has a full list.
2. Alternative, you can look it up…
   
   1. Press and hold the Option key while clicking the Apple logo in the menu bar. Then select About This Mac.
   2. On the screen that appears, which gives an overview of the hardware components, click the button named “System Report…”
   3. In the sidebar, select Controller.
   4. If you see “Apple T2 chip” on the right then, yes, your Mac has the Apple T2 Security Chip.

What’s happened with the chip?

Probably nothing fatal. Like most things these days, it can malfunction – when that occurs, you may find that perfectly acceptable passwords are no longer allowed (you can tell if this is the case as you may find that it works fine elsewhere – for example, when logging into the Mac in the first place).

If you have a fingerprint reader then you may find that this no longer seems to work anymore too (in that it will no longer prompt you to use it, but ask for passwords instead).

I experienced this recently with a MacBook Air after the Big Sur upgrade – the same login could be used to sign into the computer but wouldn’t be accepted when challenged later. Changing the password was allowed but it didn’t accept the new password either. During this time, there was never a prompt for the fingerprint reader, where there normally would be.

How to fix it

Resetting the SMC (System Management Controller) of the Mac should rectify it and it’s pretty painless to do. However, there are different instructions depending on what it’s a mobile (MacBook/MacBook Pro/MacBook Air) or desktop device (Mac/Mac Pro/Mac Mini).

Mobile

1. Shut down your Mac.
2. Press and hold the power button for 10 seconds, then release the button.
3. Wait a few seconds, then turn your Mac back on.

If that doesn’t work, then you should try this…

1. Shut down your Mac.
2. On your laptop’s keyboard (i.e. not an external one), press and hold all of the following keys…
   • Control – on the left side of your keyboard
   • Option (Alt) – on the left side of your keyboard
   • Shift – on the right side of your keyboard
3. Your Mac might turn on during this.
4. Keep holding all three keys down for 7 seconds, then press and hold the power button as well.
5. If your Mac is on, it will turn off as you hold the keys down.
6. Keep holding all four keys for another 7 seconds, then release them.
7. Wait a few seconds, then turn your Mac back on as usual.

Desktop

1. Shut down your Mac and then unplug the power cable.
2. Wait 15 seconds, then plug the power cable back in.
3. Wait 5 seconds, then switch your Mac back on using the power button.

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