Home › Forums › Macs › Desktops › Mac Pro › OpenCore › Reply To: OpenCore mattyParticipant22nd November 2021 at 11:16 am#1413946imajez.com wrote:chris 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 GPUSame problem here. I’m on High Sierra installed with DosDude1 patch and can;t upgrade my Adobe apps unless I upgrade OSX. I see you say above that indicates OpenCore is not working [which was my assumption], despite seeing a boot screen for first time in many years. So how does one fix this? Cheers imajezHi,I have seen dos dude patch messing with Open Core before, I would advise fresh install then Open Core it, in regards to downloading macOS it’s sometimes very temperamental.You can try Big Sur from here.https://www.techspot.com/downloads/1928-macos-big-sur.htmlOne thing I would want to make you aware as well is to lift it to Mojave the natural way as there is a Firmware update to 144.