rlesperance wrote:Is there an Apple procedure to avoid all the settings configuration and file transfer after the clean install ? Something like a migration process that would migrate all my stuff without starting all over again.
Not really, no. It will always carry over things that can cause issues. Never use a migration tool on a system with issues, because you will quite probably migrate the issue too.
Reality is blunt. If you want to have a safe, clean system that runs well, you start fresh and slowly reconfigure everything by hand. Trying to move or migrate stuff is asking for headaches.
Clone your existing drive, only move settings and files from the clone to the clean install by hand, and be very selective on what is moved.
I've been doing IT support for macOS/OS X since it came out and trust me, this is the best way. No "automated" method will be as clean as you need it to be.
Ross