Monday, March 19, 2018

Genius Bar Not Prepared for APFS

Charles Arthur (via Michael Yacavone):

Except that the rMBP only had a 500GB SSD. How had it got two? “Have you got a Fusion drive in here?” the Genius asked.


At this point the Genius said he suspected there was something wrong with my SSD. So he restarted the machine, held down the key to boot from a network drive, whizzed over to the one marked 10.12 and started up. Could Disk Utility read my drive now? No, it couldn’t.

“Do you have this backed up?” he asked, indicating the computer. I sure did – SuperDuper clones, and a Time Machine backup. “I think we might need to reinstall the operating system.”


That, of course, is why the Genius’s HFS+-encoded 10.12 network drive couldn’t understand my APFS-encoded SSD. So I’d wiped the hard drive for nothing.


Apple obviously needs to implement some network drives formatted with APFS. Which might mean an overhaul of how it does some stuff in-store; but it should expect that there are going to be more and more people coming in with machines that are APFS-encoded.

As I understand it, the issue is not that the boot drive has to be formatted as APFS but that it needs to be running macOS 10.13. macOS 10.12.6 supports APFS, but only the older version that does not do native normalization.

5 Comments RSS · Twitter

Apple is pretty heavy handed regarding consumers updating their Apple devices to the latest and greatest....yet their in store testing setup boots into 10.12? Am I missing something? Almost six months is a decent lead time to tool up your in store testing systems, no? The "Genius" asked if a Fusion drive was present in a system with no ability to physically install a second drive of any sort, let alone a hard drive? In other news, good to see older MBPr still having video card failures....wouldn't want those to actually get fixed or anything.

Mac Hardware test not being appreciably redesigned since Mac OS 9 is actually rather fascinating. I used it back in the early Intel OS X days....10.4-10.6 and it worked okay, but was always a "Whoa! This is retro cool experience."

At least the Genius knew how to use the darn thing. When I talked to Apple about a MBP problem back in the Snow Leopard and Lion time frame (2010/2011), the phone help (pretty sure some kind of crappy contractor as I had a friend doing tier 1 Apple support for one at the time) was dreadful. No one understood why I shouldn't have to do constant testing if I have a Hardware Test error code already in directly referencing the component I was experiencing problems with. They didn't understand what that meant at all....didn't understand much of anything, they were clearly following a checklist (I won't say script to be nice). Needless to say I returned the faulty Mac instead of hassling with a repair.

About limitations in 10.12.6 reading 10.13-formatted APFS volumes: I believe 10.12.6 it can't read encrypted APFS volumes.

That would explain why the 10.12 system could see the two volumes but not all the files: The volume with the system folders is an extra APFS volume found on bootable 10.13 systems, and the "Macintosh HD" is the main volume - that volume name is part of the unencrypted parts of an APFS volume (Contrary to FileVault2 with HFS+, where ALL blocks of a partition are encrypted, APFS encrypts blocks individually, based on which volume they belong to).

Update: Charles Arthur says that his 10.13 boot volume was not encrypted. Which now leads me to believe that the network system used by the Genius techs is not even running 10.12.6 but 10.12.4 or 10.12.5, which did not support the new file name format introduced to support normalizatition-insensitivity (which was implemented by adding a hash code to the file names in the directory entries).

@Thomas The Apple File System Guide makes it sound like even 10.12.6 only supports runtime normalization.

This clears up the diagnostic tool part of the equation:

Okay.This is soooooooo much clearer now. 2012 and older models still use Apple Hardware Test, 2013 and newer models have access to the revamped Apple Diagnostics app....

How to use Apple Hardware Test on your Mac

How to use Apple Diagnostics on your Mac

As far as why there's old network boot troubleshooting tools (Why use 10.12 at all with a 10.13 system????), I have no idea. APFS shouldn't be problematic for corporate stores to access. That's just embarrassing.

Leave a Comment