Error on partitioning - diskutil list OK?

Your Fusion disk does not look normal. A Fusion disk is usually made of a SSD at index 0 (it is the first disk) and a HDD (it is at index 1 or higher). Can you post the output of diskutil cs list which can be verified for the correct ordering?

The current partitioning looks to have had Windows at some point, because your HDD has been split into two separate chunks to build a CS volume. This is done on a 3TB fusion disk to address the MBR 2TB limit.

The UUIDs are not vulnerable. They are regenerated every time CS volumes and disks are erased, formatted or disks are added or removed from CS volumes.

On Macs prior to Late 2013 (which are preUEFI), the BC Assistant method of Windows installation uses the legacy BIOS method which has two limitations.

1. It needs a Hybrid MBR which cannot cross the 2TB boundary, and,

2. There is a limit for 4 entries in such MBRs.

A 3TB Fusion drive is split into three chunks on the HDD.

OSX (Part 1 < 2TB) + Windows

OSX (Part 2 > 2TB up to 3 TB)

If Windows is removed, the two OSX parts are supposed to be merged together when the Restore method is used in BCA. In your case, after Windows was removed, the merge part seems to have failed.

OSX (Part 1 = 2TB)

OSX (Part 2 > 2TB up to 3 TB)

This is not necessarily an issue. If you install Windows again, it should re-use and recreate

OSX (Part 1 < 2TB) + Windows

If you do not want/need to re-install Windows and address it, there are two options.

Option 1. Backup, Erase and Restore.

1. Back up OSX using Time Machine - Mac Basics: Time Machine backs up your Mac - Apple Support.

2. Boot into Internet Recovery - OS X: About OS X Recovery - Apple Support.

3. Erase your internal drive and restore from the TM backup in Step 1 - OS X Yosemite: Recover your entire system.

Please be aware that TM does not backup Bootcamp partitions.

Option 2. If the total storage used on the OSX side inside the CS volume is less than the size of the SSD, then

1. Remove the HDD from the CS volume, erase and initialize it and add it back again. This requires diskutil cs commands to be executed in Terminal.

2. Create a backup to ensure future restores bring back the modified layout not the current one.

Yes, it can slow down your Mac, depending where file blocks/chunks are located. Current design of CS is very disk space oriented, not IO performance oriented. A three-slice CS is usually slower than a two-slice CS based on my testing.

If you want to use Recovery Console then use Utilities -> Disk Utility and click on the outermost Macintosh LVG and Erase. This does not always work.

The second option to ensure proper cleanup is what I personally prefer. From Ex-Bootcamp Partition Stuck As "Free Space" ,

Using the following CS layout and UUIDs for the following commands...

|

+-- Logical Volume Group 9F877C86-814C-40D0-8D9E-45FA2DA5678B

=========================================================

Name: Macintosh HD

Status: Online

Size: 564333780992 B (564.3 GB)

Free Space: 0 B (0 B)

|

+-< Physical Volume 65391326-ABA4-4B10-B174-176C8DBDC4B4

| ----------------------------------------------------

| Index: 0

| Disk: disk1s2

| Status: Online

| Size: 120988852224 B (121.0 GB)

|

+-< Physical Volume 1DB82D0C-EB0B-40E9-BF7D-88DBF3B8FD66

| ----------------------------------------------------

| Index: 1

| Disk: disk0s2

| Status: Online

| Size: 443344928768 B (443.3 GB)

|

+-> Logical Volume Family 0DD19705-CFFB-454D-BA91-3BF49976D800

----------------------------------------------------------

Encryption Status: Unlocked

Encryption Type: None

Conversion Status: NoConversion

Conversion Direction: -none-

Has Encrypted Extents: No

Fully Secure: No

Passphrase Required: No

|

+-> Logical Volume B53F94ED-7605-4F21-B39A-66CF286B75E5

---------------------------------------------------

Disk: disk3

Status: Online

Size (Total): 555826413568 B (555.8 GB)

Size (Converted): -none-

Revertible: No

LV Name: Macintosh HD

Volume Name: Macintosh HD

Content Hint: Apple_HFS

-bash-3.2#

1. Erase LV Macintosh HD - diskutil cs deleteVolume B53F94ED-7605-4F21-B39A-66CF286B75E5

2. Erase LVG Macintosh HD - diskutil cs delete 9F877C86-814C-40D0-8D9E-45FA2DA5678B

3. Erase the internal SSD (verify that diskutil list shows SSD 120+ GB as disk0) - diskutil erasedisk JHFS+ SSD disk0

4. Erase the internal HDD (verify that diskutil list shows HDD 999+ GB as disk1) - diskutil erasedisk JHFS+ HDD disk1

5. Recreate CS LVG (Please ensure that you use the SSD first) - diskutil cs create OSX-MacintoshLVG disk0s2 disk1s2

6. Recreate the CS LV - diskutil cs createVolume OSX-MacintoshLVG "Macintosh HD" 100%

7. Restore from TM backup.

8. Re-run BCA and try to install Windows.

The verification is necessary to ensure that SSD is index 0 in the CS volume as shown in your output...

+-< Physical Volume 65391326-ABA4-4B10-B174-176C8DBDC4B4

| ----------------------------------------------------

| Index: 0

| Disk: disk1s2

| Status: Online

| Size: 120988852224 B (121.0 GB)

|

+-< Physical Volume 1DB82D0C-EB0B-40E9-BF7D-88DBF3B8FD66

| ----------------------------------------------------

| Index: 1

| Disk: disk0s2

| Status: Online

| Size: 443344928768 B (443.3 GB)

If you do not want to use Recovery Console, then OS X: Installing OS X on an external volume - Apple Support can be used to boot from an external disk and the internal HD can be erased using Disk Utility running on this external volume.

On 2012 13-in MBP with 2.7GHz i7, I currently have 1377 threads and 285 processes. Unless you feel that machine is sluggish, it should be fine.

To clean up your disk, and rebuild your CS LVG/LV, I suggest using Internet Recovery (Command+Opt+R) and using Utilities -> Terminal using the same sequence of commands. In the example, replace the UUIDs with the specific UUIDs on your local machine. Installing a fresh copy of OS X is fine. I suggest a back up of OS X before you wipe and start with a clean slate, which would provide a good backup before you wipe the disk in case it is needed.

You can also choose a "Migration" from you TM backup, if you choose not to use a "full" system Restore. Please see Move your content to a new Mac - Apple Support and the section titled Migrate from a Time Machine backup or external drive.

I suggest you run these steps when connected via wired connection, a wireless connection will be too slow.

Step 4 does not need a flash drive, since you are already in Recovery Console in step 2. Once you complete step 3, post the output of diskutil cs list of verification. Once it has been verified, exit the Terminal session and in Recovery Console click on re-install OS X. Be aware that this may not be the same version as what you currently have.

From OS X: About OS X Recovery - Apple Support,

Which version of OS X is installed by OS X Recovery?

• If you use the Recovery System stored on your startup drive to reinstall OS X, it installs the most recent version of OS X previously installed on this computer.
• If you use Internet Recovery to reinstall OS X, it installs the version of OS X that originally came with your computer. After installation is finished, use the Mac App Store to install related updates or later versions of OS X that you have previously purchased.

Once OS X is fully updated, you can run migration assistant afterwards. This allows selective migration of Accounts, Applications, Settings, etc.

The other option is to use the TM link I provided and migrate from your TM backup during the OS X installation, instead of a full restore. This allows selective restoration of Accounts, Applications, Settings, etc.