when i connect my apple cinema display (20" inch) to my iMac (early 2009), my mac crashes and goes back to the lock screen
when connected on the lock screen, both my iMac and cinema display are working fine, with the mouse working (tranfering across both screens) as you would expect, but when i try to log in, the loading icon appears for a short while on my iMac and then both screens go black and return to the lock screen.
is there a fix for this issue?
or is my Imac simpily to old to process displaying across both screens?
i had recently upgraded the RAM from 2 x 2gb to 2 x 4gb, as i thought this might help but unfortunately it hasn't.
iMac, macOS 10.15
