Boot Camp - The startup disk cannot be partitioned or restored to a single partition

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$