HELP! I have 7 partitions, 2 EFI, 2 MacHD, etc.

Missed my Edit Window...

The EFI partitions are hidden, but can be mounted with

$ mkdir /Volumes/EFI

$ sudo mount -t msdos /dev/disk0s1 /Volumes/EFI/

Password:

$ df -h

Filesystem Size Used Avail Capacity iused ifree %iused Mounted on

/dev/disk0s2 691Gi 476Gi 215Gi 69% 124782337 56295742 69% /

devfs 338Ki 338Ki 0Bi 100% 1174 0 100% /dev

/dev/disk0s4 240Gi 55Gi 185Gi 24% 115088 193850280 0% /Volumes/rMBPBCMP

map -hosts 0Bi 0Bi 0Bi 100% 0 0 100% /net

map auto_home 0Bi 0Bi 0Bi 100% 0 0 100% /home

/dev/disk0s1 197Mi 25Mi 171Mi 13% 0 0 100% /Volumes/EFI

$ diskutil unmount /Volumes/EFI

Volume EFI on disk0s1 unmounted

VMware Fusion was an example of software which enables hidden volumes, you may or may not use it. What other third-party software do you have, like NTFS-read-write tools, Disk and/or Partition Management tools?

Disk Utility has quite a few challenges with CS Volumes. The only reliable method, available as of now, is to use the diskutil cs command set to erase/expand/manage/rebuild.

Can I suggest a Disk Utility Verify/Repair (one thing that seems to work because it is not a CoreStorage command) on both the physical disks? Another approach to address such issues is by using Safe Mode boot. Useful specific key sequences are listed in Startup key combinations for Intel-based Macs - Apple Support.

There are many "hidden"commands (Apple chose not to document these), but can be found either in windows 8 does not recognise Macintosh HD, No drive Letter or http://blog.fosketts.net/2011/08/05/undocumented-corestorage-commands/.

Ravenmoon wrote:

Aside from Disk Utility and BootCamp, I don't have or use other disk or partition management software; that's one thing that makes this so odd! LOL Also, by physical disks you mean both portions of the Fusion drive, yes? Other than that, I only have the one drive giving me problems; my externals are fine.

Yes, I meant the SSD and HDD parts.

I have tried booting in SafeMode (with no other drives present [i.e. physically disconnected]), and nothing changes; the same partitions appear in DiskUtility (as below). The only difference is that the BootCamp partition does not mount. I am still unable to set my StartUp Drive to MacOS X in System Prefs; doing so returns the same error: "Building boot caches on boot helper partition failed."

What does sudo bless --info return? Bootcamp is not expected to work in Safe Mode. What files do you have in /Library/Preferences/SystemConfiguration folder. Here is my example.

ls -l /Library/Preferences/SystemConfiguration/

total 768

drwxr-xr-x 3 root admin 102 Sep 12 2013 CaptiveNetworkSupport

-rw-r--r-- 1 root wheel 7309 Jan 29 06:34 NetworkInterfaces.plist

-rw-r--r-- 1 root admin 232 Sep 12 2013 com.apple.Boot.plist

-rw-r--r-- 1 root wheel 181 Jul 8 2014 com.apple.IPConfiguration.control.plist

-rw-r--r-- 1 root wheel 2351 Mar 1 2014 com.apple.PowerManagement.plist

-rw-r--r-- 1 root wheel 321 Feb 1 2014 com.apple.accounts.exists.plist

-rw-r--r-- 1 root wheel 3368 Feb 6 09:26 com.apple.airport.preferences.plist

-rw-r--r-- 1 root wheel 231 Jul 8 2014 com.apple.eapolclient.plist

-rw-r--r-- 1 root wheel 348 Feb 6 09:26 com.apple.smb.server.plist

-rw-r--r-- 1 root wheel 331785 Feb 6 09:26 com.apple.wifi.message-tracer.plist

-rw-r--r-- 1 root wheel 17167 Jan 14 15:03 preferences.plist

If you have Xcode installed, you can open the .plist files. com.apple.Boot.plist is what can provide some interesting information.

Deleting this folder and rebooting rebuilds it, but it strongly recommended that this folder be backed up elsewhere. Customized settings can be lost otherwise.

Disk Utility Verify returns "Disk appears to be OK" on all partitions except the "Boot OS X," which it is unable to verify (the option is greyed out). My issue is not with Windows recognizing the Mac Drive; my Mac OS X partition appears in Windows just fine. My issue is the 'extra' partitions that I can't get rid of, the fact that I cannot remove all the partitions and repartition the drive, and that I can't set my startup drive to the Mac OS X partition. All of these seem to point to some kind of problem with the hidden boot partitions.

One suggestion would be to install OSX on an external volume - OS X: Installing OS X on an external volume - Apple Support

and testing a clean install of OSX. If you can reboot the Mac and then go to Applications -> Utilities -> Console logs and in the top right search box, type EFI and search, it may provide clues on what is mounting these hidden partitions. After the Debug menu was enabled, were these ever mounted by hand at least once?

1. Which of the hidden partitions I am seeing SHOULD be there for a drive with one Mac partition and one BootCamp partition, and which ones are extraneous?
2. How can I address the 'boot caches' issue so I can designate the Mac OS partition as the startup drive?
3. How can I safely remove those that are extraneous, and restore the correct structure?

(Is it possible that the Boot Camp utility could have created a Mavericks/Yosemite hybrid of some kind? I keep seeing these Core Storage issues coming up with Yosemite, but I haven't used Yosemite.... Though I used the utility in the Applications folder.....)

Your diskutil list output shows the correct ones. EFI and Recovery HD (and Apple Boot) should not be mounted by default. You should only see the LVG (Macintosh HD) and the LV (Macintosh HD - they have the same name which is another source of confusion). Bootcamp should also be visible. There should be nothing else mounted. The external disk boot may help diagnose/fix the boot caches issue. The structure is correct, but the visibility could be better. Pick one EFI volume in DU, and test if you can unmount it.

Be aware that File Vault2 and Fusion Drive both use CoreStorage, even before the advent of Yosemite (since ML 10.8.x). Try the external boot first, otherwise can you set up a Time Machine backup and backup OSX. For Bootcamp, you can use Winclone (Windows backup/restore is problematic on Macs).

I was wondering if it is Mac OS or if it is the disk structure causing these to mount. I do believe the EFI partitions are normal, but they shouldn't be mounting by default.

The 'boot from external OS X' test may cause them not to appear or if the internal disk still mounts all the EFI partitions you know the disk structure is causing it. If the disk doesn't show the partitions you can assume the OS is mounting them for some reason.

/etc/fstab is capable of mounting partitions at boot too. Lets see if you have any entries in there, in Terminal…

cat /etc/fstab

That file may not exist, so do not be alarmed if it doesn't, post the output if you have any.

My test on CS volumes on Yosemite (non-Fusion drive) does not show this behavior but I can manually mount EFI.

I'm out of my league at this point here, but I believe that it all has to do with the fusion drive. I had one for a few days and wish I had kept a screenshot of the extremely odd (to me) looking listings in DU which looked very much like the OP's. There was absolutely no way to make any sense out of it at all, especially since you basically have no control over a fusion drive, DU is a special version which only works with that fusion drive, and you're only allowed 2 partitions.

I wasn't able to learn more about it because the brand new iMac was returned as a DOA (as determined by a Genius) due to several power management problems.

I typically ignore DU on Fusion drive Macs, and stick to CLI and use diskutil cs commands. It is much cleaner for me to understand LVGs and LVs and LVFs.

I'm a happy camper now because the replacement iMac has a regular 7200 rpm drive (well, ok, an SSD would have been better, but I can't afford a 1 TB).......

Ran a test with a non-Fusion (but CS Volume) and a Reboot. EFI does not automatically mount after reboot on Yosemite 10.10.2.

with Debug turned on...

EFI has not been mounted yet...

EFI is now mounted manually...

I will test with a Mini and DU on Mavericks which has a DIY Fusion (SSD/HDD) and post back.

Try…

bless --info /

or

bless --info /Volumes/Manor

You have no /etc/fstab so that is another thing to rule out.

That looks normal, I have…

bless --info /

finderinfo[0]: 1173996 => Blessed System Folder is /System/Library/CoreServices

finderinfo[1]: 1631471 => Blessed System File is /System/Library/CoreServices/boot.efi

finderinfo[2]: 0 => Open-folder linked list empty

finderinfo[3]: 0 => No alternate OS blessed file/folder

finderinfo[4]: 0 => Unused field unset

finderinfo[5]: 1173996 => OS X blessed folder is /System/Library/CoreServices

64-bit VSDB volume id: 0xE73BFFD1189AA2E5

'bless --info' doesn't alter the setup. It tells us that partition is setup to boot using the listed folder & boot.efi.

See if this alters it…

sudo bless --folder /System/Library/CoreServices --file /System/Library/CoreServices/boot.efi --setBoot --verbose

Since you seem to be using a different boot disk you can also try selecting the startup disk from the other OS to see if that can resolve it. Other posts have said that bless helped, whilst others said that Startup disk from another disk resolved the same 'Building boot caches…' issue. They are essentially the same thing IIRC.