I upgraded to Mojave on a 5,1 MacPro. Yay for me. I'm trying to let go of my Sierra boot drive, but I can't just yet, not until I transfer everything and work out the kinks. Somethings I won't be able to, so I had been planning to keep the Sierra on an external boot. All of my drive bays and the optical bay is replaced with SSD. The Mojave Boot is on a PCIe SSD. But I have put the Sierra HD back in bay one so it can boot. It won't boot on an external enclosure.
BUT Sierra doesn't recognize the Mojave drive. Is there a way to do this? Is there an app for that? I have to boot to a High Sierra drive and THEN the Mojave SSD can be seen. Going from Mojave to the Sierra drive is easy. Going from Sierra back to Mojave is a two-step process.
BUT Sierra doesn't recognize the Mojave drive. Is there a way to do this? Is there an app for that? I have to boot to a High Sierra drive and THEN the Mojave SSD can be seen. Going from Mojave to the Sierra drive is easy. Going from Sierra back to Mojave is a two-step process.