Format & reinstall OS, things to consider?

[fridayxiii]

My trusty iMac is giving me fits all of a sudden, to the point where I think I might have to go for the nuclear option: format the HD & reinstall the OS, then bring data back from Time Machine.

I've nuked Windows PCs many times, but never had to do a fresh start on my Mac. Aside from grabbing a last backup via Time Machine, anything else to consider or be aware of?

TIA

 

[benwiggy]

The OS is on a cryptographically signed, read-only secure volume. You never need to re-install it.

Everything that you've added? Yes, you might need to wipe that. System Settings contains an option to Erase all your Data, and that should be sufficient.

OF course, if you restore it all, then you'll put everything back, including the problem.

If your computer is "giving you fits", then you need to look at everything you've put on it: background processes, login items, hardware drivers and other stuff.

 

[NoBoMac]

^This.

Before wiping anything, might try creating a new user account and see if still having problems in there. If not, might boot into safe mode to clear caches.

ADD: or can simply start using a new account if that's working fine. Move documents/files from old account to new. And reconfigure settings. But basically same amount of work if below.

If still having problems, then might want to look into erasing the MacHD - Data volume via Settings > General > Transfer or Reset. Will erase everything but the sealed OS volume.

 

[HDFan]

Aside from grabbing a last backup via Time Machine,

Make sure you have 2 other non-TM backups if you are wiping all of your data. With no 3-2-1 backup strategy in place you risk losing it all.