Q Twice recently I seem to have inadvertently hit a combination of keys that has disabled the upper case letter V on my keyboard. How can I reset that?
A Interpretation of keystrokes may be controlled in several different places, and you will need to check them all to fix this.
Look first in the Shortcuts tab of the Keyboard pane, where you can Restore Defaults. Next check that you have the correct keyboard selected in the Input Sources tab.
Then check the Accessibility pane, where odd settings in the Keyboard tool can cause this.
Finally check any third party enhancements that you might have installed, preference settings in apps that are most obviously affected, and try restarting for good measure.
Updated from the original, which was first published in MacUser volume 29 issue 11, 2013.