anyone know what this error indicates?
Mac mini; OS 11.6.1
Mac mini, macOS 10.13
Hard to say why, without knowing what’s on it.
Do you have a PC that you can use to first erase and format that flash drive?
If not, startup in macOS Recovery Mode and see if you can erase and reformat it.
What is on the flash drive?
That error indicates that the drive can not be unmounted by Disk Utility. Probably because of an installer or something else on the drive is in use.
further info: "The volume on disk2s1 couldn't be unmounted because it is in use by process 0 (kernel)"
I don't know. It is one of a bunch of discs my daughter discarded--and is a DOS-formatted disc. I do get messages about the disc somehow being in use--even immediately after it is mounted.
error -69888 trying to erase a flash drive
