After I restarted my Emacs daemon (after a couple of months uptime), I started getting plenty of errors like below during the initialisation and most of my keys stopped working:

Key sequence C-c [...] starts with non-prefix key C-c

A quick search indicated that error means the “non-prefix key” is already used. In my case, it was C-c which sounded quite weird.

I ran ag on ~/.emacs.d & luckily was able to find the culprit after a few minutes.

I had this somewhere in my init files:

(global-set-key (kbd "C-c 
s a") #'avy-goto-char-2)

Note the newline after C-c - I must have pressed ENTER by mistake and saved the file w/o paying attention.

I thought I’d share this as this may save some fellow Emacs denizens a few minutes confusing minutes.

My immediate reaction was to blame it on the upgrade to 29.1 🤦‍♂️ The morale of the story is find the blame w/i and not in Emacs!