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My Macbook Pro (10.6.8) locks up every day at noon for several minutes (and often after sleep).

I put 'Activity Monitor' up front right before noon sorted by %CPU, and saw that it ran 'fsck_hfs'. Kinda makes sense that this would make my machine unusable.

I can kinda simulate this behavior by running it by hand (or 'Disk Utility').

What is making the Mac run a disk check so often, and how do I stop/delay/fix the root cause?

There's nothing in root's crontab, and Disk Utility reports the disk is fine. I also single-user booted and ran '/sbin/fsck -fy' with no errors reported.

I do see some "LSOF: File foo left open on device" errors from 'mds' around this time - not sure if related.

share|improve this question
    
And what is the parent process of fsck_hfs? Maybe this gives you a hint which other process starts fsck_hfs... – jaume Jan 28 '13 at 19:09
    
An excellent question - since Activity Monitor doesn't show parent process and everything is locked I can't see it within there. Maybe I'll have to use 'top' next time. – Rafi Jacoby Jan 28 '13 at 20:23
    
I'd use ps -ef instead of top... – jaume Jan 28 '13 at 20:32
    
How would I use 'ps -ef' when the machine is locked up? Is there a run-in-a-loop behavior like 'top' that I'm missing in the flags? – Rafi Jacoby Jan 28 '13 at 21:15
    
Open a terminal and type while :; do date; ps -ef; sleep 2; done. The while loop prints all processes every two seconds until you press Ctrl-C. Or you could send the output to a file: while :; do date; ps -ef; sleep 2; done > ~/ps-ef_output.txt. – jaume Jan 28 '13 at 21:24

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