Boot camp

Thanks for all the help but unfortunately, I can not delete my whole disk. There is an error that it can not be made passive - I think it is called unmounted in English.

The picture states that the disc can not be erased because it can not be made passive (un mounted?)

And suddenly I have a disk image - it was not there yesterday??

Hello

Here it is:

iMac mid 2011, OS 10.13.3

Last login: Sun Mar 4 17:29:25 on console

iMac-2:~ admin$ diskutil list

/dev/disk0 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *1.0 TB disk0

1: EFI EFI 209.7 MB disk0s1

2: Apple_HFS Macintosh HD 799.0 GB disk0s2

3: Apple_Boot Recovery HD 201.0 GB disk0s3

It is this Recovery Hd I don'r understand?

Sorry but this is the respond:

Last login: Mon Mar 5 19:59:24 on console

iMac:~ admin$ diskutil unmountDisk disk0

Unmount of disk0 failed: at least one volume could not be unmounted

Unmount was dissented by PID 0

No i deleted it because i want to sell my iMac and thought everything was okay 😕

Normally booted in macOS. Don't know about Internet Recovery?

That's it! You have save my day!🙂

Thanks a lot - very nice - you know Mac!

I will - thank you very much!