have an Imac late 2013, was running El Capitan, upgraded to Catalina without doing anything about El Capitan. When I try to login, it accepts password and then goes into a endless loop. Tried first aid in utilites and tried to downld an older os .
Tried running 1St Aid from utilities and tried to reload Catalina and then tried to reload El Capitan but it won't offer any thing to help. Don't care about any data loss, just want to be able to use the computer again. Any ideas?
Yes I know I should have done more research before upgrading, had just hoped it would be ok. Also note I'm not tech. smart, just barely able to shop at Amazon and send emails so any suggestions need to be spelled out.
iMac 21.5″, OS X 10.11