BootCamp, can't partition SSD

I've upgraded my OS X to the latest Yosemite GM Candidate and cannot for the life of me figure out how to partition my SSD for BootCamp. Here are some screenshots of the problem:

And when i try to partition from Disk Utility:

What is the problem and can it be solved? I read somewhere something about needing to wipe my hard drive and start over with a fresh OS X install, but i really would prefer not to do that, any help is appreciated. Thanks.

P.S: I've tried verifying disk permissions, and repairing in recovery mode. Nothing worked.

MacBook Pro with Retina display, OS X Yosemite (10.10)

diskutil list output

/dev/disk0
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *121.3 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:          Apple_CoreStorage                         120.5 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
/dev/disk1
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                  Apple_HFS Macintosh HD           *120.1 GB   disk1
                                 Logical Volume on disk0s2
                                 D2BB45DB-C690-47B2-BFF0-E0A5D812EE6A
                                 Unencrypted
/dev/disk2
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     FDisk_partition_scheme                        *8.2 GB     disk2
   1:                 DOS_FAT_32 WININSTALL              8.2 GB     disk2s1

diskutil cs list output

CoreStorage logical volume groups (1 found)
|
+-- Logical Volume Group 312C0A5B-AC3E-4008-895F-6EDFDD386825
    =========================================================
    Name:         Macintosh HD
    Status:       Online
    Size:         120473067520 B (120.5 GB)
    Free Space:   35721216 B (35.7 MB)
    |
    +-< Physical Volume 5292E607-3F97-46C0-8E92-97BC853367D5
    |   ----------------------------------------------------
    |   Index:    0
    |   Disk:     disk0s2
    |   Status:   Online
    |   Size:     120473067520 B (120.5 GB)
    |
    +-> Logical Volume Family 736C4179-B89A-4EBE-90C7-F0CE4705D2B3
        ----------------------------------------------------------
        Encryption Status:       Unlocked
        Encryption Type:         None
        Conversion Status:       NoConversion
        Conversion Direction:    -none-
        Has Encrypted Extents:   No
        Fully Secure:            No
        Passphrase Required:     No
        |
        +-> Logical Volume D2BB45DB-C690-47B2-BFF0-E0A5D812EE6A
            ---------------------------------------------------
            Disk:                  disk1
            Status:                Online
            Size (Total):          120101797888 B (120.1 GB)
            Conversion Progress:   -none-
            Revertible:            No
            LV Name:               Macintosh HD
            Volume Name:           Macintosh HD
            Content Hint:          Apple_HFS

Solution 1:

This Mac Book Retina was originally delivered with Mountain Lion. The upgrade history contains Mavericks, several Yosemite DPs and finally the Yosemite GM Candidate.

One of the Yosemite Developer Previews transformed the previous Apple_HFS partition into a Logical Volume Group.

The (only) Logical Volume is not revertible:

The Boot Camp assistant can't modify the partition map and shrink such a LVG to free up some unallocated space for a Windows installation on a hard disk.

The only possibility (we found) to solve the problem is a complete reinstall:

1. Backup all your data
2. Disconnect all external hard drives
3. Restart into Internet Recovery Mode by pressing altcmdR
   (alternatively you may use a Mavericks or Mountain Lion Install Thumb Drive)
4. start Terminal from the menubar/utilities
5. enter following command at the Terminal prompt:

   diskutil cs list

6. Copy the Logical Volume Group (LVG) alphanumeric UUID of your CoreStorage volume. The LVG UUID should be the first listed. In the above example the alphanumeric is:
   312C0A5B-AC3E-4008-895F-6EDFDD386825.

7. Run the following command:

   diskutil cs delete UUID

   According to the number found above it would be:

   diskutil cs delete 312C0A5B-AC3E-4008-895F-6EDFDD386825

   This will delete your CoreStorage volume and your Recovery HD and reformat it as a simple HFS+ volume.

8. Quit Terminal
9. In the now opening window choose Disk Utility and format/partition/rename the internal drive. Choose 1 Partition, Mac OS Extended (Journaled) and GUID partition table (available with the option button). Quit Disk Utility.
10. Now choose 'Reinstall Mac OS X'
11. The originally shipped OS X will be downloaded and installed
12. Set up your Mac
13. Download and install Mavericks from the App Store
14. Start Boot Camp Assistant, repartiton your Mac and install Windows
15. Download and install Yosemite from the App Store

At step 10 one may boot alternatively to a Mavericks or Mountain Lion Install Thumb Drive if available and install the respective OS X.

Starting into Recovery Mode at step 3 doesn't help because it's impossible to delete the LGV then.

Solution 2:

OP, you can run the following command "diskutil cs revert" in Terminal. It will non-destructively revert Yosemite's unnecessary CoreStorage volume setup into a "normal" (non-CoreStorage) setup. I had to run in on a few of the dev previews. You may have to run it as root.