Resolved Incompatible Disk Message

[mikethebook]

With the sudden death of my 2009 Mac Mini running Mojave, I bought a refurbished 2014 Mac Mini which came with Big Sur not realising that my printer would be useless as would any non-wireless printer. So I downgraded to Mojave which appears to have been succesfull apart from an error message on opening:

Incompatible Drive: This disk uses features that are not supported on this version of macOS

There is also a new drive called Update. Can anyone tell me what's going on and what fix there is if any?

 

[mikzn]

My Guess is you did not wipe the drive / reformat to 1 partition - before installing Mojave

The drive called "Update" sounds like a remnant of of Big Sur - if that is the case you can delete it - but if it was me - I would redo the entire downgrade and install Mojave on a clean reformatted drive with only one partition

This is just a guess

 

[mikethebook]

Thanks for your reply. That doesn't explain the error message and I'm 90% sure I deleted the whole drive and reformatted to one partition. I wasn't offered the possibility of partitioning.

 

[mikzn]

Incompatible Drive: This disk uses features that are not supported on this version of macOS

Maybe I am wrong - but the "Incompatible Drive" raises a flag (IMHO) and sounds like it was created by Big Sur - and thus is not compatible with an earlier macOS - Mojave along with any other remnants of Big Sur that may be on that drive.

 

[mikethebook]

I hear what you're saying but I'll see what others say before I reinstall Mojave.

 

[chrfr]

I hear what you're saying but I'll see what others say before I reinstall Mojave.

As the earlier post said, you didn’t format the entire disk. Select “show all devices” from the view menu in Disk Utility and erase the top level device that shows.

 

[chabig]

APFS is still a work in progress and the implementations of APFS change from macOS version to version. APFS in Mojave doesn't support the features of APFS in Big Sur. You should start over and reformat the entire disk from Mojave.

 

[mikethebook]

chabig so you're agreeing that another format is called for, this time from Mojave?

And should I format for APFS or the older system? The first time I did it, maybe NOT from the top level, I was only given the choice of various forms of APFS.

 

[chrfr]

chabig so you're agreeing that another format is called for, this time from Mojave?

And should I format for APFS or the older system? The first time I did it, maybe NOT from the top level, I was only given the choice of various forms of APFS.

Yes, you need to format it again, and select APFS.

 

[mikethebook]

Operation successful! Taking all your advice here, I partitioned first to the old Journaled format using the top drive heading (found through View) then erased back to APFS before installing Mojave. There's now only the one drive and no error message. Thanks everyone!!

 

[ww2_1943]

I know this is an old thread but I was hoping someone could chime in. I want both 10.13 and 12 on my MBP. After installing 12 in in a new volume I get the incompatible disk message in 10.13. If I just ignore it will the disk eventually get corrupted or something else? Or is it eventually going to be an issue?