The information on a May 2021 post seems out of date and does not work. Can I obtain a Mojave installer and run it on an external usb hard drive in order to have dual boot capability. I had this capability until recently but something changed and it stopped working. Trying to restore this but am getting rejected when trying to obtain the Mojave installer. - thank you
Did you build a usb Installer for it?
How to create a bootable installer for macOS - Apple Support
Actually I had this trouble on a 2019 iMac, which I ordered expressly because it came with Mojave, only it didn't, it came with Catalina, luckily I had downloaded Mojave on a 2011 iMac in Preparation, but Catalina Mac said uh uh... we want you to move forward like all obedient Canon Fodder should... when steam quit coming out of my ears I used Pacifist to :Install to different drive:, worked like a charm, well as much of a charm as Apple Computing can be these days. :)
What doesn't work, I dual boot, in fact quad boot, 10.014, 10.15, 11, & 12.
Does the non booting one show upas as a boot choice if you hold Option key at startup?
Thanks for such a quick reply. My usb installed Mojave which worked for almost a year. This recently failed utterly where although I got the option, booting to it resulted with the circle bar symbol, nothing more.
I resolved to start fresh. A Mojave installer is required. Using various links I've found such as here, I'm directed to the Apple store and only a "Get" option. This option results in a rejection of the download request. Some older links in other fora sometimes lead to a link I can get to in the WayBack archive. These also eventually get picked up by the Apple store with the same result.
The problem at this time is not the dual boot, I'm comfortable I can restore this if it is allowed. Your reply suggested it should be ok. The problem is getting the installer to where I can direct it to the usb drive. - Thank you. .... - I also boot to Windows 10 (rarely) when needed.
Nice clue, will try. I've seen that itunes link before and the admonition not to use firefox; but I've not tried the safe mode option. Without it I ended up in the same apple store loop trap.
Google patcher mojave is something I've not seen; tried a dosdude mojave installer picking a usb drive as the destination but my current big sur picks picks off that move as well. Maybe the safe mode trick will get around it. - thank you
Yes, getting it on a newer OS may result in denial, no idea what Apple is thinking really.
If this doesn't work to get the Installer, there is a tool available, google patcher mojave
Try reinstalling this in Safe Mode, but not downloading using Firefox...
https://itunes.apple.com/us/app/macos-mojave/id1398502828?mt=12
Safe Boot, (holding Shift key down at startup).
Hi - Mainly I've used terminal to build the installer on the usb drive but tried something called macOS Mojave Patcher which seems to do pretty much the same thing.
Funny you mention your adventures. Mine iMac came with El Capitan and an iMacPro Yosemite (dunno it had half dome ?) but with each upgrade I kept the installers so I had quite a collection (Sierra, High Sierra, Mojave). Catalina did not shut the door but when Big Sur came along, I opted to maintain a connection to the past using the Mojave installer onto a usb drive. Recently, presumably after an upgrade, I discovered all my old installers had vanished. Hopefully I'll get there, I'm banking on this safe boot option to save the day but right now I'm in the middle of and doing one last macOS Mojave Patcher download. I'm going to halt the process and safe boot.
Then, if possible, I intend to copy the installer and rename the copy to something innocuous in case my suspicion of a Big Sur search and destroy mission is true.
There are non-apple store installer links out there. Not planning to touch that. One link out, you can trace it to Iran.
dual booting big sur and mojave
