Hi Paul Fryer,
Re: Any thoughts as to what might be the problem?
Seems fingerprints get worn down at times, so is good to have more than one to try.
Some Touch ID situations seem to work more smoothly than others.
Seems as options are greyed, you might need to use your Mac password to make any changes:
As your query is in the "High Sierra" area:
If you are using High Sierra:
Eg: A 2017 user manual Help"at:
https://help.apple.com/machelp/mac/10.12/#/mchl16fbf90a
says:
Choose Apple menu > System Preferences, then click Touch ID.
Click “Add a fingerprint,” enter your password, then follow the onscreen instructions.
You can add up to three fingerprints to your user account (your Mac can store up to five fingerprints total).
Click the checkboxes to select how you want to use Touch ID:
- Unlocking your Mac: Use Touch ID to unlock this Mac when you wake it from sleep.
- Apple Pay: Use Touch ID to complete purchases you make on this Mac using Apple Pay.
- iTunes & App Store: Use Touch ID to complete purchases you make on this Mac from the Apple online stores.
Rename and delete fingerprints
- Rename a fingerprint: Choose Apple menu > System Preferences, then click Touch ID. Click the text below a fingerprint, then enter a name.
- Delete a fingerprint: Choose Apple menu > System Preferences, then click Touch ID. Click a fingerprint, enter your password, then click Delete.
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If you are indeed using newer software than High Sierra:
See if this article helps at all: You can choose correct Mac OS at the top of article:
Use Touch ID on Mac – Apple Support
All the best :-)
