Hi,

Would really appreciate some help on this!

I tried installing Windows 7 on my iMac 2015 but during windows installation it prompted that the partition needs to be format in a different way.

Now when I try to use Boot Camp again I keep getting this message:

The startup disk cannot be partitioned or restored to a single partition.

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

The problem is that I can't erase the Boot Camp Partition in no way using Disk Utility.

If it's any help - this is the diskutil list:

haraldsiMac:~ haralddegraaf$ diskutil list

/dev/disk0 (internal, physical):

   #:                       TYPE NAME                    SIZE       IDENTIFIER

   0:      GUID_partition_scheme                        *2.0 TB     disk0

   1:                        EFI EFI                     209.7 MB   disk0s1

   2:          Apple_CoreStorage fusion                  1.7 TB     disk0s2

   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3

   4:                  Apple_HFS bootcamp                252.8 GB   disk0s6

/dev/disk1 (internal, physical):

   #:                       TYPE NAME                    SIZE       IDENTIFIER

   0:      GUID_partition_scheme                        *121.3 GB   disk1

   1:                        EFI EFI                     209.7 MB   disk1s1

   2:          Apple_CoreStorage fusion                  121.0 GB   disk1s2

   3:                 Apple_Boot Boot OS X               134.2 MB   disk1s3

/dev/disk2 (internal, virtual):

   #:                       TYPE NAME                    SIZE       IDENTIFIER

   0:                  Apple_HFS Fusion                 +1.7 TB     disk2

                                 Logical Volume on disk1s2, disk0s2

                                 0D7254CA-C937-4A69-A2AA-AC689844B16F

                                 Unencrypted Fusion Drive

/dev/disk3 (disk image):

   #:                       TYPE NAME                    SIZE       IDENTIFIER

   0:                            Boot Camp              +1.2 GB     disk3

haraldsiMac:~ haralddegraaf$

haraldsiMac:~ haralddegraaf$ sudo gpt -r show /dev/disk0

       start        size  index  contents

           0           1         PMBR

           1           1         Pri GPT header

           2          32         Pri GPT table

          34           6       

          40      409600      1  GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B

      409640  3394638832      2  GPT part - 53746F72-6167-11AA-AA11-00306543ECAC

  3395048472     1269536      3  GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC

  3396318008    16782536       

  3413100544   493666440      4  GPT part - 48465300-0000-11AA-AA11-00306543ECAC

  3906766984      262151       

  3907029135          32         Sec GPT table

  3907029167           1         Sec GPT header

haraldsiMac:~ haralddegraaf$