Wrestling with an old iMac (early 2008) which I bought second hand on ebay...
After spending almost 24 hrs trying to merely re-install the macOS (el Capitan), learnt quite a few lessons... the hard hard way!
Learnt the hard way that you need an apple ID for everything!!
But after you are forced to create an ID, you need to validate it.
Fill in your payment and billing details.
No matter on which system you created the ID, you then need to open one of the apple services (music, itunes, ...) and login and fill in your details again!!
After all this you get the message that the application (installation) is temporarily unavailable... that's because if you've not downloaded any OS before using that 'new' account, then you cannot download the required software! It requires the ID of the one who purchased it!
So you're left with no option other than use a usb to start a clean install... easier said than done!! I thought Windows was a nightmare! Apple was worse! Perhaps it would have been easier if I had another mac system - which I didn't. So had to juggle between my all-time favourite Linux and Windows.
By this time discovered a similarly distressed soul who had chronicled his struggle:
https://blog.dhampir.no/content/reinstalling-a-used-imac-20-inch-early-2008
Using the office Win. 8.1 edition system created a bootable usb. (Downloaded the el Capitan disk image file - not the rar type!!, then loaded that onto the usb using techmac or something).
Inserted into the first usb port of the backside of the iMac (when viewed from the back).
Restarted it, used CMD + R to boot from the usb. Learning from the previous site, changed the date to the present time. Got a new error message. Surprise???
Then found another apple forum which said, you don't need a usb... just change the date to mid 2017.
https://discussions.apple.com/thread/250793420
Tried that!! No success.
Then did a mix-match ... changed the date to starting of 2017, restarted it to boot from the usb... and lo and behold!!!!!!
Have el Capitan up and running on the iMac!! HURRAH!!! Thanks pretty much to the two websites and their useful info!
One down, one more to go! Hope apple does not spring any fresh surprises!
