i have owned a MBP for the last for years, just now got a 2015 MBP, am using El Capitan 10.11.3. I am using an EHD /Time Machine backups for the first time now. I dont read the answer to this question anywhere...Do I leave my EHD connected (by USB) during an Update and later this year an Upgrade? I know I should make sure I have a very current backup before doing either, just wasnt sure if I should or shouldnt disconnect the EHD while performing these two.
