hi Apple folks
my Mac Pro just had a IMMEDIATE power off while I was still working on it. an unexpected incident that shocked me so much, as i never experienced such situation with this Mac Pro which has been working well for years.
please see below the system logs for the power-off moment (about 4pm) just before last shutdown and reboot.
Sep 6 15:58:03 MACPRO mdworker: (ImportBailout.Error:1331) Asked to exit for Diskarb
Sep 6 15:58:04 MACPRO com.apple.backupd: Starting post-backup thinning
Sep 6 15:58:04 MACPRO com.apple.backupd: No post-backup thinning needed: no expired backups exist
Sep 6 15:58:04 MACPRO com.apple.backupd: Backup completed successfully.
Sep 6 15:58:04 MACPRO UserEventAgent: Failed to send message because the port couldn't be created.
Sep 6 15:58:14 MACPRO diskarbitrationd: Opera :90799 not responding.
Sep 6 15:58:14 MACPRO kernel: hfs: unmount initiated on Recovery HD on device disk0s3
Sep 6 15:58:36 MACPRO kernel: Google Chrome He triggered unnest of range 0x7fff8e000000->0x7fff8e200000 of DYLD shared region in VM map 0xfffe34adbfb473af. While not abnormal for debuggers, this increases system memory footprint until the target exits.
Sep 6 16:01:26 localhost bootlog: BOOT_TIME 1473141686 0
Sep 6 16:01:33 localhost kernel: Previous shutdown cause: 0
i powered on the Mac Pro after waiting for a short while. so far i haven't observed anything unusual and i am using this Mac to post this question.
any suggestions about how to trace down to the root cause?
thanks heaps in advance.