El Capitan Public Beta Installation Failing

Oh dear...

Offering suggestions on your numbered points:

1. I've never seen that error message before:
   • There's not even any reference of it on the web except for your thread on MacRumors.com - that's unusual in itself - it suggests that either the installer was corrupted or that the bootloader can't read the partition/drive where it resides because all the packages are contained in it - no internet access should be necessary.
   • To get Internet Recovery to work however your connection has to meet a standard detailed here: https://support.apple.com/en-ie/HT201314 (look for Supported network configurations and protocols).
2. So I would think that no, they're not connected.
   1. This will almost certainly result in a clean install (files erased)
   2. There could be; it partly depends on how far the Yosemite installer got.
      • A partition is checked by an installer to ensure that the system is suitable for the version of OS X it has to offer and one of the red flags is if a specific .plist on that partition registers that the currently installed version of OS X is later than its own. This .plist file could be altered or deleted but it may not be the only obstacle.
      • If you're going to go down that route, you could just as well attempt to re-install 10.11 (see next bullet point)
      • Either way, you'd probably want to create a bootable USB installer for 10.10.4 or 10.11. You may have trouble downloading the installer app for either via Safari running from Recovery but, if you can, then this can be done from the Terminal command line in the Utilities menu.
   3. Yes, assuming you have sufficient external storage - this can also be done from Terminal. If all you have access to, in terms of another viable OS X, are your original install disks then they'll be what you need to use to make the clean install. You'll have to boot into Disk 1 first and erase the internal drive.

If you want help with Terminal commands, we have to be at our computers at the same time. Even simple copying of files (cp -R -p -v source destination to copy a directory structure while maintaining permissions) requires knowing how your two drives are identified before the command can be used, so I'd suggest a command to enter and you'd post back the results to inform the command I'd suggest next.

Thanks for your reply. Regarding Internet Recovery—are you saying that it didn't work on my machine because my home wifi isn't WPA/WPA2? I was under the impression it wasn't working because my MBP is older. If there's a chance Internet Recovery would work, I think that's my best (easiest) bet. Would you agree?

Quoting from the support article it sounds like you've looked at:

"Some Macs that came with OS X Snow Leopard can use Internet Recovery after installing OS X Lion or later and a software update"

Depending on when in 2009 you got your MBP, this might apply to you.

As for your best/easiest bet; it depends on how your internal drive is assessed by the installer. If you're prompted "Install on ..." then this should be a benign install (leaving your User folder, Applications, etc. intact). If your only option is "Erase and install on ..." then you're obviously going to have to copy out first. This applies to all recent installers whether that be 10.10, or 10.11, or the Internet Recovery process.

My MBP was shipped with Leopard (10.5), so I don't think IR is an option for me.

What are you referring to when you said:

If you're prompted to "Install on ..." then this should be a benign install ... If your only option is to "Erase and install on ..." then you're obviously going to have to copy out first.

Where would I be "prompted" with one of those choices?

Thanks for your help. Excuse any ignorance that may come across on my end! 😊

No worries 🙂

If you create a bootable USB installer for example, it will assess the partition you select for it to install on and present you with one of those two options (or a refusal to install at all).

Two questions for you:

Is the following false in any way?:

• You downloaded the El Capitan installer via the App Store while running Yosemite (the only OS X on your internal drive or external drives) and ran it, instructing it to install over Yosemite.

If the above is true, do you have access to another Mac?

That is correct. No, I don't have access to another Mac- just my work PC running Win8.1.

Were you using OSXFUSE or NTFS apps (or similar) on your Mac to be able to write to "Windows formatted" drives from OS X?

No.

Okay. The first thing to do is to remove any drives or USBs that might be attached to your MBP and run the following three commands in Terminal (You've found it in the Utilities Menu while booted into Recovery, right?)

• diskutil repairDisk disk0
• diskutil list
• diskutil cs list

Select the output and press Cmd+C to copy it to the clipboard. Then select the Get Help Online link to open the Safari web browser and paste the output back here as a post so that I can suggest what to do next.

diskutil repairDisk disk0

Output: Repairing the partition map might erase disk0s1, proceed? (y/N)

diskutil list

Output:

/dev/disk0 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *250.1 GB disk0

1: EFI EFI 209.7 MB disk0s1

2: Apple_HFS Macintosh HD 249.2 GB disk0s2

3: Apple_Boot Recovery HD 650.0 MB disk0s3

/dev/disk1 (disk image):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme +2.1 GB disk1

1: Apple_HFS OS X Base System 1.3 GB disk1s1

/dev/disk2 (disk image):

#: TYPE NAME SIZE IDENTIFIER

0: untitled +5.2 MB disk2

/dev/disk3 (disk image):

#: TYPE NAME SIZE IDENTIFIER

0: untitled +524.3 KB disk3

/dev/disk4 (disk image):

#: TYPE NAME SIZE IDENTIFIER

0: untitled +524.3 KB disk4

/dev/disk5 (disk image):

#: TYPE NAME SIZE IDENTIFIER

0: untitled +524.3 KB disk5

/dev/disk6 (disk image):

#: TYPE NAME SIZE IDENTIFIER

0: untitled +524.3 KB disk6

/dev/disk7 (disk image):

#: TYPE NAME SIZE IDENTIFIER

0: untitled +524.3 KB disk7

/dev/disk8 (disk image):

#: TYPE NAME SIZE IDENTIFIER

0: untitled +6.3 MB disk8

/dev/disk9 (disk image):

#: TYPE NAME SIZE IDENTIFIER

0: untitled +2.1 MB disk9

/dev/disk10 (disk image):

#: TYPE NAME SIZE IDENTIFIER

0: untitled +1.0 MB disk10

/dev/disk11 (disk image):

#: TYPE NAME SIZE IDENTIFIER

0: untitled +524.3 KB disk11

/dev/disk12 (disk image):

#: TYPE NAME SIZE IDENTIFIER

0: untitled +524.3 KB disk12

/dev/disk13 (disk image):

#: TYPE NAME SIZE IDENTIFIER

0: untitled +1.0 MB disk13

/dev/disk14 (disk image):

#: TYPE NAME SIZE IDENTIFIER

0: untitled +6.3 MB disk14

diskutil cs list

Output: No CoreStorage logical volume groups found

Well done. Did you press y when it asked you if it could repair the partition map?

Don't worry, it won't erase your data disk0s1 is just the EFI partition - not OS X.

Here's the output when I pressed y:

Started partition map repair on disk0

Checking prerequisites

Checking the partition list

Adjusting partition map to fit whole disk as required

Checking for an EFI system partition

Checking the EFI system partition's size

Checking the EFI system partition's file system

Checking the EFI system partition's folder content

Checking all HFS data partition loader spaces

Checking booter partitions

Checking booter partition disk0s3

Reviewing boot support loaders

Checking Core Storage Physical Volume partitions

Updating Windows boot.ini files as required

The partition map appears to be OK

Finished partition map repair on disk0

There's a small chance that repairing the partition map will have fixed the problem, so it's worth trying the "Reinstall OS X" option while you're still in Recovery Mode.

Still getting the "An error occurred while preparing the installation. Try running this application again." error.