Today I just could not connect to my MacMini which was displaying a screensaver when I turned the screen off this morning. Usually it works fine when I come back home and turn it back on, but this time it only showed up a black screen, meaning the screen was connected and it was resuming from sleep.
So let’s investigate this
Before trying anything else, back to the basis : it replies to ping - good, so OSX hasn’t crashed.
ssh and Screen Sharing (VNC) also work - so I click on Apple/Retart, all the windows clause but nothing else happens. The VNC connection is not closed.
Weird. I try the same by ssh : sudo then reboot - but reboot also fails with :
/ is busy updating; waiting for lock
Weird. Let’s check /var/log/system.log:
May 23 18:30:57 macmini com.apple.kextcache: Lock acquired; proceeding.
May 23 18:30:57 macmini com.apple.kextcache: /: helper partitions appear up to date.
May 23 18:30:59 macmini AppleFileServer: _Assert: /SourceCache/afpserver/afpserver-585.2/afpserver/../afpserver/SharePointSyncTask.cpp, 215 (4294967253)
May 23 18:31:25: —- last message repeated 1 time —-
May 23 18:31:25 macmini com.apple.backupd: Starting standard backup
May 23 18:31:25 macmini com.apple.backupd: Error -35 while resolving alias to backup target
May 23 18:31:35 macmini com.apple.backupd: Backup failed with error: 19
Weird. After some googling, I see hackintosh users have the same problem with a wrong ACPI VGA kext, but maybe backupd is causing the problem? A killall -9 backupd later :
May 23 18:31:52 macmini com.apple.launchd (com.apple.backupd): Exited: Killed: 9
Let’s try again to reboot
May 23 18:32:06 macmini reboot: rebooted by guylhem
May 23 18:32:06 macmini reboot: BOOT_TIME: 1337812326 786930
Time for some deep thinking - so I remember about anything I may have done this morning - but I only did one unusual thing : I cleaned my desk. How could it be related??
Morale of the story: in OSX there can be weird bugs too. A misconnected mini DVI cable *can* apparently cause backupd to fail, while still powering the display to wake it up from suspend, but causing reboot problems and preventing a normal boot due to the kext - just like on a hackintosh.