Yesterday I tried to install Win10 through bootcamp, but it couldn't install it on the premade partition. Eager as I was i meddled with the partition scheme during the installer but with no result.

While in pain that I couldn't get my dual boot right, I wanted to reset the partition-table by using bootcamp, only it gave me this error:

The startup disk must be formatted as a single Mac OS Extended (Journaled) volume or already partitioned by Boot Camp Assistant for installing Windows.

I'm currently stuck using DiskUtils to delete the partitions and make my HDD whole again. But it won't work.

This is the output from diskutil list

/dev/disk0 (internal, physical):
#:                       TYPE NAME                    SIZE              IDENTIFIER
0:      GUID_partition_scheme                        *500.3 GB   disk0
1:                        EFI EFI                     209.7 MB   disk0s1
2:          Apple_CoreStorage Macintosh HD            401.4 GB   disk0s2
3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
4:                        EFI NO NAME                 104.9 MB   disk0s4
5:         Microsoft Reserved                         16.8 MB    disk0s5
6:                        EFI NO NAME                 104.9 MB   disk0s6
7:                  Apple_HFS Backup                  96.7 GB    disk0s7
/dev/disk1 (internal, virtual):
#:                       TYPE NAME                    SIZE       IDENTIFIER
0:                  Apple_HFS Macintosh HD           +401.0 GB   disk1
                             Logical Volume on disk0s2

My Mac model is MacBook Pro mid 2015.

The desired goal is to lose all partitions, including the "Backup" partition, which I can not seem to delete using the Disk Utility application. Eventually, I want to have a single Mac partition, which is required by the Boot Camp Assistant application to install a Windows 10.

Any advice?


  • I would advise you to update your answer with the model/year of your Mac. Also, what is your desired goal? Do you want to keep "Backup" volume? How large of a Windows volume do you want? Jun 2, 2016 at 16:32
  • Hi David, thank you for your reply. Model is macbook pro mid 2015. The desired goal is to lose all partitions, incl. the "backup" partition, which i can't seem to delete in diskutil. Eventually i want to have a single mac partition which can afterwards be formatted by bootcamp to install a win10.
    – Kickar
    Jun 3, 2016 at 3:50

1 Answer 1


I would assume the same procedure would be followed as the answer posted to this question "Merge Partitions with Disk Utility in El Capitan Gives operation Failed error".

In other words, the commands would be as shown below.

diskutil  erasevolume  "Free Space"  ""  /dev/disk0s7
diskutil  erasevolume  "Free Space"  ""  /dev/disk0s6
diskutil  erasevolume  "Free Space"  ""  /dev/disk0s5
diskutil  erasevolume  "Free Space"  ""  /dev/disk0s4
diskutil  cs  resizestack  F6E64063-7D4B-4D75-AAC5-C4D128919CD3  0

Note: You need to keep partitions disk0s1, disk0s2 and disk0s3.

I would advise executing the command diskutil list after entering each of the above commands. If something unexpected happens, send me a comment.


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