Bootcamp Assistant trouble with Startup disk

[mfg3000]

"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."

Can anyone help me solve this? I have looked for a couple hours how to solve it and I haven't really made any progress.

diskutil list incase anyone wants to see it.

/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_CoreStorage Macintosh HD            999.3 GB   disk0s2

/dev/disk1 (internal, virtual):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                  Apple_HFS Macintosh HD           +999.0 GB   disk1
                                 Logical Volume on disk0s2
                                 E5E2EA32-1BCB-4E0D-9644-9B5FF3F75884
                                 Unlocked Encrypted

/dev/disk2 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     FDisk_partition_scheme                        *63.1 GB    disk2
   1:               Windows_NTFS WININSTALL              63.1 GB    disk2s1