Home › Forums › Macs › Desktops › Mac Pro › OpenCore › Reply To: OpenCore mattyParticipant10th November 2021 at 10:39 am#1413561chris wrote:Hi, thanks for posting this — I have got as far as step 3 fine — the EFI is working, I get the boot screen. Going to System Preferences/Software Update I only get the option to upgrade to Monterey. What is the procedure to upgrade to Catalina form this point? I have tried downloading the full installer and that doesn’t work (I get the message “This version of macOS 10.15 cannot be installed on this computer”.Thanks for your help, ChrisSystem: MacPro 5,1 mid2010. 2 x 3.46GHz OSX 10.14.6 Radeon RX590 GPUHi Chris,Can you try with Big Sur just to check? The message that you receive points to compatibility with the machine which would indicate Open Core not working.Link for macOS’s https://support.apple.com/en-gb/HT211683