Home Forums Mac Software Mac Operating Systems High Sierra not an option in Startup Disk

I run a drive that always has the latest OS, but still use Yosemite as my main system. I found that in High Sierra, all my systems (Yosemite and Snow Leopard) are offered as startup options. However, in Yosemite, the High Sierra drive is not shown at all. In fact, that drive will not even appear in the Finder window side bar. All other drives are there, including the old Sierra backup.

I read something about a new system file arrangement in High Sierra. Is that what my problem is? The old file system won't acknowledge the new?

I can choose to boot in High Sierra when I start up using the Alt key, so the world hasn't come to an end. It's just a bit of a nuisance.