IMAC 27 inch Mid 2011
How can I update my mac OS High Sierra on my mac 27 inch mid 2001?
iMac 27″, macOS 10.13
Question marked as
Sorry, 10.13.6 is the highest update for a 2011 iMac.
See the following from Identify your iMac model - Apple Support
iMac (27-inch, Mid 2011)
Model Identifier: iMac12,2
Part Number: MC813xx/A, MC814xx/A
Latest compatible operating system: macOS High Sierra 10.13.6