Command, tab, and mouse click not working, rest of keyboard and mouse movement still works

Question

A few days ago I posted about how my macbook pro had a glitch where everything except the volume, brightness, and mouse movement stopped working.

I am now having a similar but very distinct problem on the same device. Now, the entire keyboard works, but the cmdtab shortcut to switch applications, the cmdspace shortcut to search, and the caps lock key do not work (caps lock did work in the other glitch).

Weirdly, I can type cmdT to open a new tab in Chrome, so the key itself must work. Unlike in the other glitch, I can use the tab key as well.

Any ideas on how I can troubleshoot this?

Answer 1

This is a puzzler and at first I was thinking, "wonky keyboard or keyboard controller."

But before I go blaming hardware it would be best to see if the issue is related to software.

Most, if not all, keyboard customizations are done on a user by user basis and if they are not set in System Preferences they would be set by something that ran at login or startup.

1. Restart your Mac while holding the ⇧ Shift key. When you see the Apple logo you can release the key. Startup may take a lot longer. If that fixes the issue there is something installed that is causing the issue. If nothing changes...
2. Create another user. Log in as that user. Still have the problem? Hopefully not. If not then there is something in your user profile messing with your keyboard. You can start deleting/moving/etc. preference files and the like, but I would be inclined to just migrate your files to the new profile and delete the old one.

Neither one of these worked? Add your results to your original question and we will take another stab at it.