Cannot erase disk
Erasing “APPLE SSD...” (disk0) and creating “Untitled”
Unmounting disk
Couldn’t open device. : (-69877)
Operation failed…
Anyone who knows?
MacBook Pro 15″, macOS 10.15
User profile for user:
JessS19
User level:
Community Specialist
Greetings trond808,
Start by ensuring that you are following the steps below in order to unmount your disk:
"Unmount a disk set
- In the Disk Utility app
on your Mac, select the disk set that you want to unmount in the sidebar. - Click the Unmount button
in the toolbar or beside the disk set name.
After unmounting a disk set, you can disconnect the disk members of the set from your computer." Unmount a disk set or disk member using Disk Utility on Mac
If the issue continues, test to see if you can unmount the disk in safe mode. This is a way of starting your computer that prevents certain software from opening. It can take longer than normal to restart: How to use safe mode on your Mac
We hope this helps!
Sincerely.