Weefrustrated wrote:
How can i update to macOS Catalina 15612.4.9.1.8 when my computer does not bring up this update when requested via software update?
You do not say what year iMac...? there are hardware limitations
Big Sur Tech specs
• MacBook (2015 or later)
• MacBook Air (2013 or later)
• MacBook Pro (Late 2013 or later)
• Mac mini (2014 or later)
• iMac (2014 or later)
• iMac Pro (2017 or later)
compare your Catalina Technical Specifications - Apple Support
https://support.apple.com/kb/SP803?locale=en_US
System requirements macOS 10.15 Catalina
macOS Catalina will run on all Macintosh computers that supported Mojave:
MacBook: Early 2015 or newer
MacBook Air: Mid 2012 or newer
MacBook Pro: Mid 2012 or newer
Mac Mini: Late 2012 or newer
iMac: Late 2012 or newer
iMac Pro
Mac Pro: Late 2013 or newer; Mid 2010 or Mid 2012 if upgraded with a recommended Metal-capable GPU
• Mac Pro (2013 or later)
The older macOS installer backups on this server:
https://support.apple.com/en-us/HT211683
verify you are using the Safari browser to download/initiate the macOS links.