System Preferences - Startup Disk?

[bladerunner88]

Running Mojave on a Mac Pro (6.1) recently installed Big Sur on a partition. When am booted into Big Sur both Operating Systems show up in the Startup Disk and can boot from Big Sur into Mojave. However when am in 10.14.6 Big Sur does not appear as an option in the Startup Disk Window?

Any ideas on how I can get Big Sur to appear? Or is it a 32 Vs 64 Bit thing?
tried the "Bless" command line in Terminal which seemed too do not much of anything cept saying it could not recorgniose the Volume even tho it appears in Disk utility.....

TIA

 

[DeltaMac]

Yes, there's big differences between the boot system from Mojave to BigSur, even more if you decide to go to Ventura.
Easiest work-around is to simply restart, then hold the Option key so you go into the boot picker screen. Choose your other system from there.

 

[bladerunner88]

Yes, there's big differences between the boot system from Mojave to BigSur, even more if you decide to go to Ventura.
Easiest work-around is to simply restart, then hold the Option key so you go into the boot picker screen. Choose your other system from there.

Hey DeltaMac Copy All -Thanks for the Intel.

Cheers!

 

[bogdanw]

Or is it a 32 Vs 64 Bit thing?

It's an APFS thing ... Different macOS versions have different APFS versions. Disks/volumes formated with a newer version are not mounted by default by older version, presumably to prevent damaging them. If you run First Aid in Disk Utility you will see some warnings like
"warning: container has been mounted by APFS version 2142.101.3, which is newer than 1934.141.2”
“warning: disabling overallocation repairs by default; use -o to override”

 

[bladerunner88]

Hey bogdanw - oh wow, ok that makes sense had not thought of that. However I'am getting a little dialog box when I Boot into Mojave saying something about "This Disk is incompatible due to newer..... (I forget the exact wording pre-coffee 😂 ) Thanks for the confirmation, was wondering if I had messed up the install somehow.

 

[DeltaMac]

I dual boot with Mojave and Ventura.
Mojave complains that there is an "Incompatible disk. This disk uses features that are not supported on this version of macOS"
That's likely the same message that you see, and is just telling you that the older system cannot fully use the volume(s) used by the newer system

 

[bladerunner88]

Ah Copy Copy that's what I Get - Cheers.

 

[Frame2023]

Yes, there's big differences between the boot system from Mojave to BigSur, even more if you decide to go to Ventura.
Easiest work-around is to simply restart, then hold the Option key so you go into the boot picker screen. Choose your other system from there.

Doesn't work for me. I installed Ventura on the blade SSD of my 27" iMac Mid 2017, Mojave resides on the SSD in the drive bay. Once Ventura is successfully installed and I boot into Mojave, I get the "Incompatible disk. This disk uses features that are not supported on this version of macOS" - message. But Ventura is also "lost". It does not show in the boot picker screen while booting holding the option key.

 

[bladerunner88]

Frame2023 are you using a Bluetooth Keyboard? I found that when wanting to Boot into Big Sur using the "holding down the Option Key Method" I needed to hardwire the Kboard to the Mac, as during the reboot the Bluetooth doesn't seem to initiate so your keyboard input does not register, Once I used the USB to lightning cable the Boot Screen would appear and you could select your OS of choice.

 

[DeltaMac]

Doesn't work for me. I installed Ventura on the blade SSD of my 27" iMac Mid 2017, Mojave resides on the SSD in the drive bay. Once Ventura is successfully installed and I boot into Mojave, I get the "Incompatible disk. This disk uses features that are not supported on this version of macOS" - message. But Ventura is also "lost". It does not show in the boot picker screen while booting holding the option key.

I have several Macs, with a variety of multiple boot system installs.
Sometimes, booting to another system on the same Mac doesn't work (can't see the choice in the boot picker screen), until I reset NVRAM. Now, that is usually because it's an older Mac, with Ventura installed via OCLP, which can really mess with the boot process.
Even if OCLP is not in use - an NVRAM reset may help get your bootdrive(s) to appear correctly in the boot picker screen.

 

[Frame2023]

NVRAM - reset did not help... Installed Monterey, same behavior. It is 18,3 iMac, so fully compatible with Ventura.

 

[Frame2023]

Update: I did do a fresh install of Mojave on the blade.
Installed Ventura over Mojave - works! Ventura can be chosen now while option booting.
Now I have Mojave and Sierra on the slower Samsumg 870 EVO Sata SSD,
Ventura on the blade. Both worlds, the better software from 2011
and the latest from 2023 combined in one machine.
Many thanks for the advices!