Whale hunting

A few weeks ago I noticed my aged cheesegrater Mac was experiencing issues at boot. It wasn’t urgent – I am not using it on a day to day basis but still would like it to remain operable.

This entry is a troubleshooting log to help me keep track of symptoms observed and solutions attempted.

HARDWARE SPEC: The Mac Pro is a 2009 4,1 flashed to a 5,1 and maxed out for hardware upgrades.

This is from a current System Report. The unit had been configured to boot at midnight and back up to an onboard HD so there is still bootable access to the system and files and I have booted to that volume in order to run various diagnostics on the boot-compromised SSD.

  •   Model Name: Mac Pro
  •   Model Identifier: MacPro5,1
  •   Processor Name: 6-Core Intel Xeon
  •   Processor Speed: 3.46 GHz
  •   Number of Processors: 2
  •   Total Number of Cores: 12
  •   L2 Cache (per Core): 256 KB
  •   L3 Cache (per Processor): 12 MB
  •   Hyper-Threading Technology: Enabled
  •   Memory: 32 GB
  •   Boot ROM Version:
  •   SMC Version (system): 1.39f5
  •   SMC Version (processor tray): 1.39f5

The unit’s drive bays are full, it’s maxed out for RAM, and there is a multi-modal expansion card provisioning additional USB and I believe Lightning, and the video card is a Radeon RX 580 supporting three displays at the moment. One of the quirks of the 5,1 flash is instability in onboard wifi and sound so there may be upgrades to those as well, I do not recall offhand. The system is running on 10.16.x Mojave in order to retain access to a large suite of 32bit production tools on the unit.

Interestingly under ‘Storage’ an unexpected volume is reported which does not display in the finder when booted into the backup: GoogleSoftwareUpdate-, which I would guess may be a clue, if, for example, this was an automated update to Drive that was somehow interrupted.

SYMPTOMS: On boot, the initial grey screen and progress bar seems normal. The unit then flips over to display the desktop and the various startup processes instantiate. The top menu bar is displayed, various notification popups come show up upper right, and as the startup processes happen they show in the menubar. However when it is time for the desktop to populate with icons and for the Dock to instantiate, the finder appears to crash. During these crashes at first it is possible to access various functions via the Apple Menu, such as the System Report via About this Mac. However after an indeterminate number of crashes the menubar is no longer redrawn and these functions are inaccessible.

Accessing Force Quit during this accessible period is possible and appears to allow the user the opportunity to force quit the finder, however the restarting Finder replicates its’ uninterventioned behavior.

Holding the shift key down in this cycle has no effect.

Apple suggests restarting into safe mode by holding the space bar down from just after the starting chime until the startup screen is visible. For whatever reason, I have found this to be hit or miss. When it does successfully invoke safe mode, the startup progress bar takes much, much longer than usual – up to 30 minutes. Then, when the startup process shifts to drawing the desktop, rather than populating the screens with the desktop image, a white spinning windmill circle displays, the cursor is drawn in the upper left corner of the outboard display, and the process appears to crash, and then enters a loop that must be ended by force-shutdown.

Cursory web research has not located similar symptomologies. Startup issues and boot loops appear to generally take effect during the initial startup screen phase rather than at the desktop instantiation phase. One highly anecdotal report suggested that a change to the way that Google has implemented Drive meant that users who neglected to update an older version of Drive could experience a similar set of symptoms. I have yet to investigate that; however it seems unlikely to me as the cloned copy of the system boots fine.

Running Disk Repair on the affected volume neither resolves the issue nor reports any problems.

In short, my flashed cMP 5,1 under Mojave
a) won’t boot in safe mode
b) boots into what looks like a Finder crash loop on instantiating the desktop
c) has a CCC-maintained bootable backup that works fine
d) will boot into Recovery Mode and Disk Utility reports no underlaying HW issues with the boot volume ond no issues with the data structure on the disk.

I think it must be an issue with a Startup Item, but without Safe Mode, I can’t get there.

If I were solving this in a production environment I would just overwrite the boot drive with that CCC backup but I would like to know why this is happening so I will be spending an hour a day on it for a bit.

I have crossposted to MacRumors here: