I'm running OS X Sierra 10.12.6 on my three Macs and, for software reasons, don't want to upgrade for a while. However, one application will be orphaned next year and requires High Sierra or later. Is it possible to create a boot disk on a Micro SD card with High Sierra on it, when I've never upgraded my other Macs? Is it still possible to run two systems on the same Mac?
Thanks.
You can boot a Mac from an external source as long as it is formatted Mac OS Extended (Journaled) and GUID partition scheme (to make it bootable). Now, I cannot answer the question about your Micro SD Card because I do not know if that would be powerful enough to boot an OS; and, even if it is, the process would be very slow and painful. I'd suggest you get a decent external hard drive, format it, and then you could clone your current OS to it. After that, go to the app store and get the other installer and direct it to your external drive. However, another risk: depending on your Mac model/year, you may not find HS available. It is only available if your Mac will not support Mojave or you've downloaded it previously.
You can boot a Mac from an external source as long as it is formatted Mac OS Extended (Journaled) and GUID partition scheme (to make it bootable). Now, I cannot answer the question about your Micro SD Card because I do not know if that would be powerful enough to boot an OS; and, even if it is, the process would be very slow and painful. I'd suggest you get a decent external hard drive, format it, and then you could clone your current OS to it. After that, go to the app store and get the other installer and direct it to your external drive. However, another risk: depending on your Mac model/year, you may not find HS available. It is only available if your Mac will not support Mojave or you've downloaded it previously.
Got it. I have a few 250GB drives around. So, I'll make one into a bootable disk and upgrade the system on that disk, if I understand it right.
The devices from which you can boot do not require a separate Driver to be loaded to function normally. Their Drivers are built into MacOS, and that is why you can boot from them.
I do not know about any SD cards, but you can certainly boot from USB thumb drives if set up properly. Keep in mind MacOS needs an additional over 9GB free space on the boot drive to start up, and that is not counting anything needed for Swap files.
Boot From A MicroSD Card
