On top of what Daniel said, while it has nothing to do with your specific problem, Emacs version 23 is incredibly old. You really should upgrade it. I don't even think recent versions of SLIME runs on it. 

Regards, 
Elias 

On Mon, 10 Aug 2020, 19:14 Daniel Kochmański, <daniel@turtleware.eu> wrote:
Hello Oscar,


‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Monday, 10 August 2020 12:52, Oscar Chappel <oachappel@yahoo.com> wrote:

> Good morning,
> I’m having an issue loading McClim on my MacBook Pro. I’m running Mac OS Catalina version 10.15.6, Emacs version 23.6 with slime and SBCL.

Keep in mind that currently, McCLIM requires X-server running, because there is no native cocoa backend.

>
> I have quicklisp installed. When I execute (ql:quickload :mcclim) the process starts and then I get the error “No symbol named STANDARD-OPTIMIZED-SETTINGS in CL-PPCRE.
>
> Can anyone tell me what I’m missing?

It seems like some of your libraries on which McCLIM depends are out of sync. Please confirm that:

1. you've run  ql:update-all-dists
2. you don't have lingering old versions of libraries in common-lisp/ or ~/quicklisp/local-projects etc.

>
> Thanks,
> Oscar Chappel

Best regards,
Daniel

--
Daniel Kochmański ;; aka jackdaniel | Przemyśl, Poland
TurtleWare - Daniel Kochmański      | www.turtleware.eu

"Be the change that you wish to see in the world." - Mahatma Gandhi