I bought a used 2019 MBP 16, unfortunately the seller put Monterey on it so I want to downgrade. I've followed the Apple guides and other online instructions and they just won't work. Before someone comments that Mojave is old and newer versions are better etc I know, but some of my apps don't work on Catalina and newer so I need Mojave.
First off the MBP plain refuses to download any macOS installer from the App Store (says update not found), so I downloaded it from my 2013 MP running Mojave and created a bootable USB after transferring the installer file to my MBP (if that makes a difference?).
Upon restarting and trying to boot into the install drive, it shows up an incompatible sign like (/) just like when using old apps on Catalina. This is already after downgrading from Monterey to Big Sur, and Big Sur to Catalina with a clean install each time. According to the install guides, this shouldn't be happening. Am I doing something wrong? It shouldn't be my USB C to A adapter or flash drive since they worked fine with the other downgrades.
First off the MBP plain refuses to download any macOS installer from the App Store (says update not found), so I downloaded it from my 2013 MP running Mojave and created a bootable USB after transferring the installer file to my MBP (if that makes a difference?).
Upon restarting and trying to boot into the install drive, it shows up an incompatible sign like (/) just like when using old apps on Catalina. This is already after downgrading from Monterey to Big Sur, and Big Sur to Catalina with a clean install each time. According to the install guides, this shouldn't be happening. Am I doing something wrong? It shouldn't be my USB C to A adapter or flash drive since they worked fine with the other downgrades.