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

Hi all, I'm trying to remove the partition of my Windows bootcamp but i keep getting "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." error. I am on MacOs High Seirra Version 10.13.3 beta and when i ran diskutil list on terminal, i get this:

/dev/disk0 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *251.0 GB disk0

1: EFI EFI 209.7 MB disk0s1

2: Apple_APFS Container disk1 200.0 GB disk0s2

3: Apple_KernelCoreDump 655.4 MB disk0s3

4: Microsoft Basic Data BOOTCAMP 50.0 GB disk0s4

/dev/disk1 (synthesized):

#: TYPE NAME SIZE IDENTIFIER

0: APFS Container Scheme - +200.0 GB disk1

Physical Store disk0s2

1: APFS Volume Macintosh HD 106.4 GB disk1s1

2: APFS Volume Preboot 20.2 MB disk1s2

3: APFS Volume Recovery 518.2 MB disk1s3

4: APFS Volume VM 1.1 GB disk1s4