How can I determine hold old my operating system is, compared to other operating systems?
Trying to fix some other problems on my old Mac desktop, and the method used will depend on whether it is older then some but earlier than others.
iMac 27″, macOS 11.4
Scroll down to the Releases portion of this wickipedia page. It gives the names and dates of release of all the system 10 OSs.
To find out the exact date on which you first installed a system hold down the Option key and select System Information from the menu.
In the left hand pane click on Installations under Software.
The numbers will be higher on more-recent releases; multiple numerals inside a pair of periods are a single number. If you only have the names, the releases are Cheetah, Puma, Jaguar, Panther, Tiger, Leopard, Snow Leopard, Lion, Mountain Lion, Mavericks, Yosemite, El Capitan, Sierra, High Sierra, Mojave, Catalina, and Big Sur in order.
(199421)
Age of Operating system
