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How Do I Downgrade Catalina To Mojave?

I just erased and completely reset my mid-2012 MacBook Air but the reinstall replaced Mojave 10.14.6 with Catalina 10.15.4. My app for running my Dahua home cameras will not work with Catalina and Dahua has no update. I need to replace Catalina with Mojave. When I attempted to download Mojave from App Store, I received a message that “Install macOS” application is too old to be opened on this version of macOS. Suggestions?

Comments: 4 Responses to “How Do I Downgrade Catalina To Mojave?”

    3 years ago

    It sounds like you used the wrong version of recovery mode, so you got the latest version of macOS instead of an earlier one. See

    Downgrading will be difficult because you have to wipe everything and reformat the entire drive, then restore. Risky and time-consuming.

    I would encourage you to stick with Catalina. You will have to upgrade eventually as your old 2012 Mac won't last forever. So if the manufacturer has abandoned those cameras, then it is perhaps time to move on and get new ones. I hate it when manufacturers do that, but you have to treat it like those cameras are now "broken." Why stick with an old OS forever because they can't get their act together or have failed as a company? Just my two cents.

    Douglas Brace
    3 years ago

    Tom, you can do this by doing five things: (1) backup anything and logout of any Apple services... (2) download the Mojave installer... (3) create a USB Mojave USB installer... (4) boot to the USB installer, open Disk Utility and completely erase your drive... (5) install macOS Mojave. Appleā€™s website has guides on their website (you can find them by doing a Google search) for some of these steps and so do other websites.

    Dana Stevens
    3 years ago

    A while ago I used time machine to revert to an earlier version of Mac OS so I could continue using Duet Display. The disadvantage of course is that you lose any data that has been added since the upgrade to the version you want to revert from. I believe is the procedure I used. It has been a while so I don't remember how long the process took but it worked fine for me.

    Dana Stevens
    3 years ago

    From earlier post. Obviously you can save data prior to reverting to the older Mac OS to avoid losing the data when you revert. I'm not disagreeing with Gary about sticking with Catalina but if you have a time machine backup then using it to revert should be an option.

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