padams35
Level 2 (168 points)
Desktops

Q: System Crash recovery

My mid 2011 iMac running Yosemite 10.10.4 recently suffered a hard crash the likes of which I have not seen since OS9. On restart the computer initially suffered keyboard recognition problems and later exhibited critical beach ball infestation that left the computer unusable for any practical application.

 

What I have tried:

Disk Utility permission repair - no effect

Upgrading to Yosemite 10.10.5 - no effect

Apple Hardware test - reported no errors

Safe Boot - just as slow

Cleared ~/Library Cache, Saved Application State, and LaunchAgent files - This provided a massive temporary performance boost but within the hour half of the beachballs had returned.

 

What else can I safely delete in /Library or ~/Library?

Is there anything else I should try before reformatting the hard drive and reinstalling the OS?

iMac, OS X Yosemite (10.10.5)

Posted on Mar 13, 2016 12:21 PM

by padams35,Solvedanswer
padams35 padams35
Level 2 (168 points)
Desktops
A:

Yah, Other World Computing has always been highly recommended but the only firewire drives they sell appear to be enclosures. That might be the way to go for an SSD upgrade but for this quick-restore I cheaped out and bought a bus-powered G-Drive mobile off the shelf from my local Fry's.

 

Installing OSX to the external drive took a little longer than the internal drive reinstall, but so far performance between the two is comparable enough that I now plan on upgrading to El Capitan on one for a side-by-side OS performance comparison.

 

Anyway, it doesn't look like my internal is in the process of failing and if it does fail I now know I can boot to an external HDD.

 

So, Problem/Solution Summery.

1) My Problem: Systematic lag, latency, and beach balls across most applications following a virtual box crash with the following additional symptoms:

      a) Slowness persisting despite both CPU and RAM utilization being low

      b) kernel[0]: disk0s#: I/O errors reported in console log

      c) Disk failure errors reported by EtreCheck

      d) No drive errors reported by DiskUtility

2) What I did that fixed the problem:

      a) Rebooted using my TimeMachine backup volume as restore disk

      b) Reformatted main HD

      c) Zeroed out HD

      d) Reinstalled OS

      e) Restored only User data

3) Presumably not every step I took was required, but I was frustrated and wanted burn everything to the ground for a clean new start.


Other Lessons Learned

1) Timemachine backups work as bootable restore drives

2) Pay attention to your backups: Excluding the recent history snapshots I made post-crash I had nothing until April 2015. Either my 3+ year old time machine archive had quietly switched to annual snapshots or I had gotten way too lazy with my monthly backup routine. Thankfully any crash corruption had not damaged my recent user data.

3) If I did this again I would have created a 2nd backup to a different drive before reformatting. Oops. Thankfully nothing went wrong.

Posted on Mar 16, 2016 11:33 AM

Close
padams35

Q: System Crash recovery

  • All replies
  • Helpful answers

  • by a brody,Helpful

    a brody a brody Mar 14, 2016 11:30 AM in response to padams35
    Level 9 (66,882 points)
    Classic Mac OS
    Mar 14, 2016 11:30 AM in response to padams35

    Logs you are really the only thing you can safely delete from the library files.  The rest are supporting documents for various applications.

     

    A safe boot minimizes the startup items and kernel extensions.

    Your Mac's PRAM battery is probably getting old (at four years it does).

    The other thing to consider is running Etrecheck to look for anything you installed that should not be installed.

     

    We can look at the resulting system report from Etrecheck to tell you if there is anything else that may be wrong:

     

    http://www.etrecheck.com/

     

    And no, system updates will not fix system slowness issues.

  • by padams35,

    padams35 padams35 Mar 13, 2016 12:59 PM in response to a brody
    Level 2 (168 points)
    Desktops
    Mar 13, 2016 12:59 PM in response to a brody

    Etrecheck is trying to insist that performance is 'Good' but also noted that the Macintosh HD had >500 errors with a Drive failure warning. Since neither DiskUtility nor the Apple Hardware test found anything wrong with the disk I suspect those errors are reflecting some other problem.

     

    [code]

    Macintosh HD (disk0s2) / : 968.70 GB (721.18 GB free) - 515 errors

    Drive failure![/code]

  • by BobHarris,

    BobHarris BobHarris Mar 13, 2016 2:38 PM in response to padams35
    Level 6 (19,633 points)
    Mac OS X
    Mar 13, 2016 2:38 PM in response to padams35

    You could try actually posting the entire EtreCheck output as a reply, so we can look at it.

     

    You could also post some of the panic reports so that they can be analyzed.

    Kernel Panic reports: "/Library/Logs/DiagnosticReports"

    <http://support.apple.com/kb/ht2546>

    <http://support.apple.com/en-us/HT200553>

    The panic report should have "panic" in the file name.

     

    And the errors that EtreCheck is reporting are what was found in the OS X logs.  Generally when a disk driver decides it can no longer do hundreds of retries and instead reports and error that OS X logs, your disks is going downhill on Roller Skates.

     

    If you choose to ignore this, I would suggest you at least keep backups.  Lots and lots of up-to-date backups.

  • by padams35,

    padams35 padams35 Mar 13, 2016 3:21 PM in response to BobHarris
    Level 2 (168 points)
    Desktops
    Mar 13, 2016 3:21 PM in response to BobHarris

    EtreCheck version: 2.9.8 (258)

    Report generated 2016-03-13 14:31:17

    Download EtreCheck from https://etrecheck.com

    Runtime 3:12

    Performance: Good

     

    Click the [Support] links for help with non-Apple products.

    Click the [Details] links for more information about that line.

     

    Problem: Beachballing

     

    Hardware Information: ⓘ

        iMac (21.5-inch, Mid 2011)

        [Technical Specifications] - [User Guide] - [Warranty & Service]

        iMac - model: iMac12,1

        1 2.7 GHz Intel Core i5 CPU: 4-core

        12 GB RAM Upgradeable - [Instructions]

            BANK 0/DIMM0

                2 GB DDR3 1333 MHz ok

            BANK 1/DIMM0

                2 GB DDR3 1333 MHz ok

            BANK 0/DIMM1

                4 GB DDR3 1333 MHz ok

            BANK 1/DIMM1

                4 GB DDR3 1333 MHz ok

        Bluetooth: Old - Handoff/Airdrop2 not supported

        Wireless:  en1: 802.11 a/b/g/n

     

    Video Information: ⓘ

        AMD Radeon HD 6770M - VRAM: 512 MB

            iMac 1920 x 1080

     

    System Software: ⓘ

        OS X Yosemite 10.10.5 (14F27) - Time since boot: about 8 days

     

    Disk Information: ⓘ

        ST31000528AS disk0 : (1 TB) (Rotational)

            EFI (disk0s1) <not mounted> : 210 MB

            Macintosh HD (disk0s2) / : 968.70 GB (730.38 GB free) - 561 errors

    Drive failure!

            Recovery HD (disk0s3) <not mounted>  [Recovery]: 650 MB

            Recovery HD (disk0s4) /Volumes/Recovery HD  [Recovery]: 650 MB (128 MB free)

            disk0s5 (disk0s5) <not mounted> : 1 MB

            disk0s6 (disk0s6) <not mounted> : 25.72 GB

            disk0s7 (disk0s7) <not mounted> : 4.27 GB

     

        HL-DT-STDVDRW  GA32N   ()

     

    USB Information: ⓘ

        Logitech USB Receiver

        Apple Computer, Inc. IR Receiver

        Apple Internal Memory Card Reader

        Apple Inc. FaceTime HD Camera (Built-in)

        Mitsumi Electric Hub in Apple Extended USB Keyboard

            Mitsumi Electric Apple Extended USB Keyboard

        Apple Inc. BRCM2046 Hub

            Apple Inc. Bluetooth USB Host Controller

     

    Thunderbolt Information: ⓘ

        Apple Inc. thunderbolt_bus

     

    Gatekeeper: ⓘ

        Mac App Store and identified developers

     

    Kernel Extensions: ⓘ

            /Library/Application Support/VirtualBox

        [loaded]    org.virtualbox.kext.VBoxDrv (5.0.14 - 2016-02-09) [Support]

        [loaded]    org.virtualbox.kext.VBoxNetAdp (5.0.14 - 2016-02-09) [Support]

        [loaded]    org.virtualbox.kext.VBoxNetFlt (5.0.14 - 2016-02-09) [Support]

        [loaded]    org.virtualbox.kext.VBoxUSB (5.0.14 - 2016-02-09) [Support]

     

    System Launch Agents: ⓘ

        [not loaded]    6 Apple tasks

        [loaded]    154 Apple tasks

        [running]    52 Apple tasks

     

    System Launch Daemons: ⓘ

        [not loaded]    47 Apple tasks

        [loaded]    136 Apple tasks

        [running]    81 Apple tasks

     

    Launch Daemons: ⓘ

        [loaded]    com.adobe.fpsaud.plist (2016-01-11) [Support]

        [not loaded]    org.freedesktop.dbus-system.plist (2015-03-27) [Support]

        [loaded]    org.macosforge.xquartz.privileged_startx.plist (2013-11-10) [Support]

        [not loaded]    org.virtualbox.startup.plist (2016-02-09) [Support]

     

    User Launch Agents: ⓘ

        [loaded]    com.valvesoftware.steamclean.plist (2016-03-13) [Support]

     

    User Login Items: ⓘ

        None

     

    Other Apps: ⓘ

        [running]    com.etresoft.EtreCheck.112212

        [running]    com.valvesoftware.steam.43200

        [running]    com.valvesoftware.steam.ipctool

        [loaded]    org.freedesktop.dbus-session

        [loaded]    org.macosforge.xquartz.startx

        [loaded]    373 Apple tasks

        [running]    154 Apple tasks

     

    Internet Plug-ins: ⓘ

        Flip4Mac WMV Plugin: 2.4.4.2 (2012-08-12) [Support]

        FlashPlayer-10.6: 18.0.0.194 - SDK 10.6 (2015-06-28) [Support]

        QuickTime Plugin: 7.7.3 (2016-02-23)

        Flash Player: 18.0.0.194 - SDK 10.6 (2015-06-28) Outdated! Update

        Default Browser: 600 - SDK 10.10 (2016-02-23)

        PepperFlashPlayer: 20.0.0.286 - SDK 10.6 (2016-01-21) [Support]

        Silverlight: 5.1.10411.0 - SDK 10.6 (2012-08-13) [Support]

        JavaAppletPlugin: 15.0.0 - SDK 10.10 (2014-02-16) Check version

     

    Safari Extensions: ⓘ

        Adblock Plus (2016-01-05)

        ClickToFlash (2016-01-03)

        DuckDuckGo (2015-07-10)

     

    3rd Party Preference Panes: ⓘ

        Flash Player (2016-01-11) [Support]

        Flip4Mac WMV (2012-05-15) [Support]

     

    Time Machine: ⓘ

        Auto backup: YES

        Volumes being backed up:

            Macintosh HD: Disk size: 968.70 GB Disk used: 238.32 GB

        Destinations:

            TOSHIBA EXT [Local]

            Total size: 749.81 GB

            Total number of backups: 44

            Oldest backup: 6/5/13, 9:09 PM

            Last backup: 2/23/16, 7:05 AM

            Size of backup disk: Adequate

                Backup size 749.81 GB > (Disk used 238.32 GB X 3)

     

    Top Processes by CPU: ⓘ

             3%    WindowServer

             2%    fontd

             1%    kernel_task

             0%    steam_osx(2)

             0%    dpd

     

    Top Processes by Memory: ⓘ

        782 MB    kernel_task

        172 MB    mds_stores

        111 MB    Finder

        111 MB    steam_osx(2)

        98 MB    cfprefsd(2)

     

    Virtual Memory Information: ⓘ

        6.00 GB    Free RAM

        6.00 GB    Used RAM (6.91 GB Cached)

        0 B    Swap Used

  • by padams35,

    padams35 padams35 Mar 13, 2016 3:39 PM in response to padams35
    Level 2 (168 points)
    Desktops
    Mar 13, 2016 3:39 PM in response to padams35

    The hard disk errors are really the only red flags in the EtreCheck report.

     

    The Console log appears more unsettling.

    ...

    3/13/16 6:18:54.292 PM QuickLookSatellite[4371]: [QL] No sandbox token for request <QLThumbnailRequest stackshot.log>, it will probably fail

    3/13/16 6:18:54.292 PM QuickLookSatellite[4371]: [QL] No sandbox token for thumbnail request file:///Library/Logs/stackshot.log, it will probably fail

    3/13/16 6:18:57.265 PM iconservicesd[59]: Failed to move temp file /Library/Caches/com.apple.iconservices.store/F4C6515F-3D37-3D98-EA80-3AF13A1F47 2A.isdata.tmp to /Library/Caches/com.apple.iconservices.store/F4C6515F-3D37-3D98-EA80-3AF13A1F47 2A.isdata with error: Error Domain=NSCocoaErrorDomain Code=516 "“F4C6515F-3D37-3D98-EA80-3AF13A1F472A.isdata.tmp” couldn’t be moved to “com.apple.iconservices.store” because an item with the same name already exists." UserInfo=0x7fcac97917a0 {NSSourceFilePathErrorKey=/Library/Caches/com.apple.iconservices.store/F4C6515F -3D37-3D98-EA80-3AF13A1F472A.isdata.tmp, NSUserStringVariant=(

        Move

    ), NSDestinationFilePath=/Library/Caches/com.apple.iconservices.store/F4C6515F-3D3 7-3D98-EA80-3AF13A1F472A.isdata, NSFilePath=/Library/Caches/com.apple.iconservices.store/F4C6515F-3D37-3D98-EA80 -3AF13A1F472A.isdata.tmp, NSUnderlyingError=0x7fcac97915e0 "The operation couldn’t be completed. File exists"}

    3/13/16 6:18:57.474 PM iconservicesd[59]: Failed to move temp file /Library/Caches/com.apple.iconservices.store/F4C6515F-3D37-3D98-EA80-3AF13A1F47 2A.isdata.tmp to /Library/Caches/com.apple.iconservices.store/F4C6515F-3D37-3D98-EA80-3AF13A1F47 2A.isdata with error: Error Domain=NSCocoaErrorDomain Code=516 "“F4C6515F-3D37-3D98-EA80-3AF13A1F472A.isdata.tmp” couldn’t be moved to “com.apple.iconservices.store” because an item with the same name already exists." UserInfo=0x7fcac9714560 {NSSourceFilePathErrorKey=/Library/Caches/com.apple.iconservices.store/F4C6515F -3D37-3D98-EA80-3AF13A1F472A.isdata.tmp, NSUserStringVariant=(

        Move

    ), NSDestinationFilePath=/Library/Caches/com.apple.iconservices.store/F4C6515F-3D3 7-3D98-EA80-3AF13A1F472A.isdata, NSFilePath=/Library/Caches/com.apple.iconservices.store/F4C6515F-3D37-3D98-EA80 -3AF13A1F472A.isdata.tmp, NSUnderlyingError=0x7fcac9790d00 "The operation couldn’t be completed. File exists"}

    3/13/16 6:18:58.860 PM QuickLookSatellite[4371]: In -[NSApplication(NSQuietSafeQuit) _updateCanQuitQuietlyAndSafely], _LSSetApplicationInformationItem(NSCanQuitQuietlyAndSafely) returned error -50

    3/13/16 6:19:06.336 PM Finder[251]: Layout still needs update after calling -[TListScrollView layout].  TListScrollView or one of its superclasses may have overridden -layout without calling super. Or, something may have dirtied layout in the middle of updating it.  Both are programming errors in Cocoa Autolayout.  The former is pretty likely to arise if some pre-Cocoa Autolayout class had a method called layout, but it should be fixed.

    3/13/16 6:19:24.293 PM Console[4374]: Failed to connect (_consoleX) outlet from (NSApplication) to (ConsoleX): missing setter or instance variable

    3/13/16 6:19:26.325 PM com.apple.xpc.launchd[1]: (com.apple.imfoundation.IMRemoteURLConnectionAgent) The _DirtyJetsamMemoryLimit key is not available on this platform.

    3/13/16 6:19:43.000 PM kernel[0]: disk0s2: I/O error.

    3/13/16 6:19:57.000 PM kernel[0]: disk0s2: I/O error.

    3/13/16 6:19:57.889 PM systemstatsd[388]: assertion failed: 14F27: systemstatsd + 3258 [934DD34F-EAF0-3DE6-B4A9-6DD998596D75]: 0xa

    3/13/16 6:20:12.000 PM kernel[0]: disk0s2: I/O error.

    3/13/16 6:20:27.000 PM kernel[0]: disk0s2: I/O error.

    3/13/16 6:20:27.190 PM systemstatsd[388]: assertion failed: 14F27: systemstatsd + 3297 [934DD34F-EAF0-3DE6-B4A9-6DD998596D75]: 0xa

    3/13/16 6:22:26.876 PM com.apple.xpc.launchd[1]: (com.apple.imfoundation.IMRemoteURLConnectionAgent) The _DirtyJetsamMemoryLimit key is not available on this platform.

    3/13/16 6:22:55.000 PM kernel[0]: disk0s2: I/O error.

    3/13/16 6:23:09.000 PM kernel[0]: disk0s2: I/O error.

    3/13/16 6:23:09.695 PM systemstatsd[388]: assertion failed: 14F27: systemstatsd + 3258 [934DD34F-EAF0-3DE6-B4A9-6DD998596D75]: 0xa

    3/13/16 6:23:25.000 PM kernel[0]: disk0s2: I/O error.

    3/13/16 6:23:39.000 PM kernel[0]: disk0s2: I/O error.

    3/13/16 6:23:39.216 PM systemstatsd[388]: assertion failed: 14F27: systemstatsd + 3297 [934DD34F-EAF0-3DE6-B4A9-6DD998596D75]: 0xa

    3/13/16 6:26:40.000 PM kernel[0]: disk0s2: I/O error.

    3/13/16 6:26:53.000 PM kernel[0]: disk0s2: I/O error.

    3/13/16 6:26:54.001 PM systemstatsd[388]: assertion failed: 14F27: systemstatsd + 3258 [934DD34F-EAF0-3DE6-B4A9-6DD998596D75]: 0xa

    3/13/16 6:27:09.000 PM kernel[0]: disk0s2: I/O error.

    3/13/16 6:27:23.000 PM kernel[0]: disk0s2: I/O error.

    3/13/16 6:27:23.085 PM systemstatsd[388]: assertion failed: 14F27: systemstatsd + 3297 [934DD34F-EAF0-3DE6-B4A9-6DD998596D75]: 0xa

     

    However, the DiagnosticReports folder contains no kernel panic fails. There are an assortment of recent powerstats.diag logs with a few older awdd.awd documents and a couple of wakeups_resource.diag reports that I think occurred before the crash, but no panics. I've attached the latest log contents below for reference.

     

     

    Date/Time:       2016-03-12 00:00:00 -0500

    OS Version:      10.10.5 (Build 14F27)

    Architecture:    x86_64

    Report Version:  19

     

     

    Event:           powerstats

    Signature:       com.apple.SystemStats.TopPkgPowerEvent

    Start time:      2016-03-12 00:00:00 -0500

    End time:        2016-03-12 00:10:10 -0500

    Duration:        610s

    Steps:           0

     

     

    Hardware model:  iMac12,1

    Active cpus:     4

     

     

    ================================================================

                   Rank:: 3

     

     

     

     

    CPU Summary

    ===========

          Avg. Frequency: 2.161 GHz

          Package Power:: Pkg: 6.75W, CPU 1.74W, GPU: 0.26W

      Pkg Interrupt Rate: Total: 500Hz   ARPT/DSB3/HDAU/RP02: 29Hz   EHC1/HDEF: 43Hz   EHC2: 1Hz   GFX0: 60Hz   IPI: 7Hz   SATA: 244Hz   TMR: 116Hz

         Pkg C-State Res: Total: 90.1%   C2: 29%   C3: 0%   C6: 61%

       Cores C-State Res:   C3: 0%   C6: 97%

     

     

    Apps & Daemons (grouped by coalition)

    =====================================

    Ranked by CPU & Energy Impact:

    00:00:10 1.6 % 5760.95 com.apple.system

    00:00:16 2.7 % 1677.98 com.apple.Safari

    00:00:00 0.1 % 68.00 com.apple.systemstatsd

    00:00:00 0.0 % 63.00 com.apple.watchdogd

    00:00:00 0.0 % 58.00 jp.co.canon.cijscannerregister

     

     

    Ranked by Interrupts / Idle Wakeups:

    245616 (403.3/sec) 237807 wkups (403.3/sec) com.apple.system

       3212 (5.3/sec)   3043 wkups (5.3/sec) com.apple.watchdogd

       2338 (3.8/sec)   2195 wkups (3.8/sec) jp.co.canon.cijscannerregister

        580 (1.0/sec)    551 wkups (1.0/sec) org.ntp.ntpd

        228 (0.4/sec)    191 wkups (0.4/sec) com.apple.Spotlight

     

     

    Ranked by Process Launches (incl. XPC svcs. & fork()):

          0 com.apple.AddressBook.SourceSync

          0 com.apple.ocspd

          0 com.apple.syncdefaultsd

          0 com.apple.Spotlight

          0 com.apple.DataDetectorsDynamicData

     

     

     

     

    Devices Dashboard

    =================

      Display Brightness: 89.0%

                Wi-Fi on: 00:10:09 (100% of total)

         Discrete GPU on: 00:00:00 (0% of total)

            Bluetooth on: 00:10:09 (100% of total)

  • by BobHarris,

    BobHarris BobHarris Mar 13, 2016 6:38 PM in response to padams35
    Level 6 (19,633 points)
    Mac OS X
    Mar 13, 2016 6:38 PM in response to padams35

    You have 2 different RAM card sizes.  This generally indicates you have 3rd party RAM installed.  It is always possible the RAM is causing problems, but generally failing RAM does not result in disk errors being reported, rather it tends to just panic the system.

     

    I think you disk is failing, so I would backup, then backup, and keep backing up until you get the disk replaced.

  • by a brody,

    a brody a brody Mar 14, 2016 8:56 AM in response to BobHarris
    Level 9 (66,882 points)
    Classic Mac OS
    Mar 14, 2016 8:56 AM in response to BobHarris

    Agreed with Bob.    Your hard drive is likely toast, though getting the right RAM makes sense.  Especially if you think your RAM is from any other source than:

     

    http://www.macsales.com/

    http://www.crucial.com/

    http://www.datamem.com/

    http://www.lifetimememory.com/

     

    or Apple.    These four vendors allow you to be very specific that you want RAM for a mid-2011 iMac.    Not all 1333 MHz PC3-10600 DDR3 SO-DIMMs (204-pin)

    are the same.  Only those tested with a mid-2011 iMac will work with yours.

  • by padams35,Apple recommended

    padams35 padams35 Mar 14, 2016 11:30 AM in response to a brody
    Level 2 (168 points)
    Desktops
    Mar 14, 2016 11:30 AM in response to a brody

    The 8GB of extra RAM was manufactured by Crucial and was installed by myself a little over a year ago. So far its been working great.

     

     

    I reformatted the hard drive last night, zeroed out the partition, reinstalled the OS, and just finished restoring my user data from the time machine backup. The process took twice as long as I was expecting but was completed with less than half the frustration I feared. So far Safari hasn't given me any beachballs and Half life 2 runs smoothly. Not the most scientific of benchmarks and still too early to declare victory but I'm cautiously optimistic that the system is back to where it was before the crash.

     

    Just to be safe I'm now shopping around for a Firewire 800 hard drive that I can use as an external boot volume if the iMac's internal hard drive does end up going down.

  • by a brody,

    a brody a brody Mar 16, 2016 8:47 AM in response to padams35
    Level 9 (66,882 points)
    Classic Mac OS
    Mar 16, 2016 8:47 AM in response to padams35

    The best ones I know of are from http://www.macsales.com/

     

    I am not affiliated with them in any manner.  Just a very happy customer since 1991.

  • by padams35,Solvedanswer

    padams35 padams35 Mar 16, 2016 11:33 AM in response to a brody
    Level 2 (168 points)
    Desktops
    Mar 16, 2016 11:33 AM in response to a brody

    Yah, Other World Computing has always been highly recommended but the only firewire drives they sell appear to be enclosures. That might be the way to go for an SSD upgrade but for this quick-restore I cheaped out and bought a bus-powered G-Drive mobile off the shelf from my local Fry's.

     

    Installing OSX to the external drive took a little longer than the internal drive reinstall, but so far performance between the two is comparable enough that I now plan on upgrading to El Capitan on one for a side-by-side OS performance comparison.

     

    Anyway, it doesn't look like my internal is in the process of failing and if it does fail I now know I can boot to an external HDD.

     

    So, Problem/Solution Summery.

    1) My Problem: Systematic lag, latency, and beach balls across most applications following a virtual box crash with the following additional symptoms:

          a) Slowness persisting despite both CPU and RAM utilization being low

          b) kernel[0]: disk0s#: I/O errors reported in console log

          c) Disk failure errors reported by EtreCheck

          d) No drive errors reported by DiskUtility

    2) What I did that fixed the problem:

          a) Rebooted using my TimeMachine backup volume as restore disk

          b) Reformatted main HD

          c) Zeroed out HD

          d) Reinstalled OS

          e) Restored only User data

    3) Presumably not every step I took was required, but I was frustrated and wanted burn everything to the ground for a clean new start.


    Other Lessons Learned

    1) Timemachine backups work as bootable restore drives

    2) Pay attention to your backups: Excluding the recent history snapshots I made post-crash I had nothing until April 2015. Either my 3+ year old time machine archive had quietly switched to annual snapshots or I had gotten way too lazy with my monthly backup routine. Thankfully any crash corruption had not damaged my recent user data.

    3) If I did this again I would have created a 2nd backup to a different drive before reformatting. Oops. Thankfully nothing went wrong.