macos – An unknown partition type in diskutil on Mac OS : FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF Partition: How to Save data

thanks in advance for your support and help.

I am using MacAir – Big Sur 2015 with 256 Gb hard drive. Hard Drive was portioned in 3: 2x 100GB (Main and Sub) as APFS and 1X 50 GB as ExFat to install Ubuntu. Later on, I decided to do partitioning of 100 GB Sub drive into 5 Gb and 95 Gb so shat I can use 5Gb drive as a shared drive to be used by both Ubuntu and Mac. I wanted to add files and access files in this 5G drive from either Ubuntu or Mac. I still don’t know which Format I should use (ExFat, keep APFS or etc)


I made a mistake while portioning. I had some important data on Sub drive. When I partitioned, my data stayed in 5Gb drive and now I cannot access the file. As you can see on the screenshot, isI put my data on 5 Gb partition, but I cannot see it now. Yes, data is important and I want to save it. I see that this post could help me but I cannot move forward due to following reasons. I am also new at terminal. I want to set up Ubuntu as a second OS to work. All these things happened cause of this. I will be happy if you could help me with this problem. We can do connect with team viewer too. Thank you so much for the help in advance.

As you can see, my partition that I need is fun of FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF. I cannot even see this 5Gb partition in DiskUtil.

Terminal screenshot


I followed the link: How do I recover/fix my OS X partition?

Errors I received:

I tried this command and got an error: gpt -r show disk0 gpt show: unable to open device ‘disk0’: Permission denied

I used following command but there is again an errorr.:
diskutil unmountdisk disk0

Unmount of disk0 failed: at least one volume could not be unmounted Unmount was dissented by PID 1 (/sbin/launchd) Dissenter parent PPID 0 (kernel_task)

But I was not able to achieve the goal. What I would like to have is to have my data in this 5G drive safely and later I will take care of of shared data and install ubuntu. As you can imagine I am new in Terminal and coding. I am going to train myself in pyThon for research project and that’s the reason I need Ubuntu.

thanks and regards