For the benefit of anyone else with this issue this is how I fixed my Fusion Drive (macOS CoreStorage Volume) without messing up my BootCamp Partition (for Windows 10 Pro).
Warning: The macOS side will get wiped.
- Turn off computer
- Detach any external drives (especially backup drive)
- Boot to Recovery Mode withcmdRor Internet Recovery Mode withaltcmdRafter chime sound
Note: If you're having trouble try using a wired Apple keyboard plugged directly into machine.
- From macOS Utilities Menu Bar Select Utilities → Terminal
- Type diskutil list to see a list of your Disks
Joshuas-iMac:~ joshua$ diskutil list
/dev/disk0 (internal, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *121.3 GB disk0
1: EFI EFI 209.7 MB disk0s1
2: Apple_CoreStorage Fusion 121.0 GB disk0s2
3: Apple_Boot Boot OS X 134.2 MB disk0s3
/dev/disk1 (internal, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *1.0 TB disk1
1: EFI EFI 209.7 MB disk1s1
2: Apple_CoreStorage Fusion 703.3 GB disk1s2
3: Apple_Boot Recovery HD 650.1 MB disk1s3
4: Microsoft Basic Data BOOTCAMP 296.0 GB disk1s4
/dev/disk2 (internal, virtual):
#: TYPE NAME SIZE IDENTIFIER
0: Macintosh +818.5 GB disk2
Logical Volume on disk0s2, disk1s2
13509204-211B-4AEB-8641-591C3C074A79
Unencrypted Fusion Drive
Note: Your disks will likely be laid out the same but pay close attention if they're not.
disk0 = 128GB Internal Physical Solid State Drive (~121GB)
disk1 = 1TB Internal Physical Hard Disk Drive (~1TB)
disk2 = CoreStorage Logical Volume made up of ~121GB SSD (disk0s2) and ~703GB HDD (disk1s2) = ~818GB
Type diskutil cs list to see a list of your CoreStorage Volumes
Joshuas-iMac:~ joshua$ diskutil cs list
CoreStorage logical volume groups (1 found)
|
+-- Logical Volume Group FBF87405-FADB-460B-98AF-40CF33427462
=========================================================
Name: Fusion
Status: Online
Size: 824333869056 B (824.3 GB)
Free Space: 32768 B (32.8 KB)
|
+-< Physical Volume E3763A6D-3A0D-4425-A83F-29E99D3C94FE
| ----------------------------------------------------
| Index: 0
| Disk: disk0s2
| Status: Online
| Size: 120988852224 B (121.0 GB)
|
+-< Physical Volume 9A47FDDE-D391-40AE-93D2-69FFA026C285
| ----------------------------------------------------
| Index: 1
| Disk: disk1s2
| Status: Online
| Size: 703345016832 B (703.3 GB)
|
+-> Logical Volume Family AA17DBB3-D6E3-4CF1-ADD6-6022A80B91B2
----------------------------------------------------------
Encryption Type: None
|
+-> Logical Volume 13509204-211B-4AEB-8641-591C3C074A78
---------------------------------------------------
Disk: disk2
Status: Online
Size (Total): 818478579712 B (818.5 GB)
Revertible: No
LV Name: Macintosh
Volume Name: Macintosh
Content Hint: Apple_HFS
LVG Type: Fusion, Sparse
Note: If you want more info you can type diskutil info /dev/disk0 or disk1 or disk2 etc.
- Type diskutil unmountDisk /dev/disk2 to unmount your CoreStorage Logical Volume (disk2 for me)
- Type diskutil cs deleteVolume LogicalVolumeUUID (long number after Logical Volume)
(ex: diskutil cs deleteVolume 13509204-211B-4AEB-8641-591C3C074A78)
Type diskutil cs delete LogicalVolumeGroupUUID (long number after Logical Volume Group)
(ex: diskutil cs delete FBF87405-FADB-460B-98AF-40CF33427462)
Quit Terminal
Breathe 🙂
- Open Disk Utility
- You should now see your SSD and HDD as separate drives. Rename them to 'SSD' and 'HDD' if you want.
- Leave your BootCamp Partition alone.
- Quit Disk Utility
Smile, you're almost there 🙂
- From macOS Utilities Menu Bar Select Utilities → Terminal
- Type diskutil list to see a list of your Disks
- Type diskutil cs create "Name" SSDIdentifier HDDIdentifier to make a new CoreStorage Group
(ex: diskutil cs create Fusion disk0s2 disk1s2)
Note: When you create the new CoreStorage Group make sure you're using your SSD and HDD.
Most likely you'll use sector 2 of the SSD (disk0s2) and sector 2 of the HDD (disk1s2)
- Type diskutil cs CreateVolume SameUUIDofGroupYouJustMade jhfs+ "Macintosh HD" 100%
- Type diskutil cs list to see your new Logical Volume made of the SSD (disk0s2) and HDD (disk1s2)
- Quit Terminal
So close! 🙂
- Open Disk Utility
- Run First Aid on your new Fusion Drive, it should be happy.
- Quit Disk Utility
- Still in recovery mode / internet recovery mode, from macOS Utilities install a new clean version of macOS
- After it's all done run through setting up the new stuff.
- Shutdown the machine.
- Attach your Time Machine Backup External Drive.
- Boot up into the new system.
- While you're logged in launch Migration Assistant to restore from your latest backup. (You can choose stuff)
- If all goes well you should end up with your old user settings and files just like they were along with your BootCamp Partition still in tact.
Give yourself a high five for being pro 🙂
If you encounter any problems along the way write to me and I'll try to help.
