How To Reinstall Macos Catalina From Usb

Hi – I have been having some issues on my late 2013 Imac since upgrading to Catalina. A lot of library messages in the logs for example. Sometimes if I go to shutdown I get a black screen for a while then it reboots, other times it’s fine. Sometimes when emptying the bin it just sits there on the screen and other odd behaviours. Have run Malwarebytes and nothing untoward there.

Installing Macos Catalina From Usb

Quit the OS X Mountain Lion installation by clicking the menu item Quit Install OS X. Click the Disk Utility item to open the disk manager. Click the Show all disks menu to list all hidden disks. Select the disk that you want to create the partition. Format the disk with Mac OS Extended (Journaled) format on the right side erase. The simplest way to reverse an OS update is to restore from an earlier Time Machine backup - one you made before upgrading to Big Sur (or Catalina if you want to go back further).

Installing Os X Catalina

It’s got very frustrating so I thought I might try and download Catalina again and refresh it. Using the Recovery, Installed OS option, does this download a new copy of the OS to the Macintosh HD partition while keeping Macintosh HD-Data partition separate? I have a Time Machine backup and also other separate copies of the three users Photos library from the iMac but wanted to know if I can re-install the OS without specifically doing anything else to keep my data. Sorry if this is basic question but in Mac terms I am not that experienced.
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Gregory