Erasing a usb stick
running into the attached problem. help.
MacBook Pro 13″, macOS 13.6
Hi,
Following document could help your issue.
“Couldn't Unmount Disk” errors usually appear in Disk Utility when the boot drive is busy. As a first line step be sure to close all open files and programs and try again. If the error persists, reboot the computer and try again.
If it doesn't help, try to erase USB memory stick by other Mac or PC if you or your friends have.