Read-only file system when attempting mkdir /data/db on Mac

Question

I am trying to create a new folder in the main directory

Tried all kinds of examples

sudo mkdir /data/db

sudo mkdir -p /data/db<

Answer 1

Mac version Catalina made the root folder is no longer writable.

Brew has an updated version of mongodb to use a new path (which it creates itself), /usr/local/var/mongodb and following these instructions will fix the issue:

Guide to installing updated mongodb-community-edition

brew install mongodb-community@VERSION where the first VERSION with the fix is 4.2