Reality501 Said:
"Settings - keyboard or ???: Recently, when I type " or ' there is a line under the character. Most of the time, if I type another character, all is well. Sometimes, it deletes the " or '.[...]"
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Five Thoughts:
A. Check Autocorrect:
See if these are listed as autocorrect items. Go here: Check Spelling and Grammar on Mac - Apple Support
B. Reset the SMC and NVRAM:
Sometimes changes are made to the system and then settings (i.e. for keyboard) become manipulated, technically. So, reset both on your Mac.
C. Use An External Keyboard:
It Doesn't have to be Apple brand. You might need this adapter: USB-C to USB A Adapter - Apple. So, try the keyboard, seeing if you get the same error.
D. Single-Out this User:
Try creating a new administrator user, seeing if you still get this error. If not, then it is an error with the current user. So, what you would do is transfer everything over to this new user, and then trash this current user.
As a Last Restort:
E. Reinstall the macOS:
The drivers went missing somehow. So, reinstall the macOS. Nothing would be deleted. It's just that items that have become corrupted or deleted, would be replaced or reinstalled back to where they should be. Go Here: How to reinstall macOS from macOS Recovery - Apple Support.
Important: Be certain to create a backup of your Mac prior to all of this. That way, you can have something to restore from the Mac from, should anything go wrong with the reinstall.
