Hi all, I searched thé forum for earlier dock-disappeared posts and found no similar situations, so I start this new thread to seek help. In short, everything worked well this morning and thé machine shutdown normally. But thé dock disappeared this afternoon when I powered it on. In the Console tool - all messages window, I found thé following: 12-11-08 22:50:30,000 kernel: disk0s2: I/O error. 12-11-08 22:50:31,396 com.apple.launchd.peruser.501: (com.apple.Dock.agent) Job appears to have crashed: Bus error: 10 12-11-08 22:50:31,846 ReportCrash: Saved crash report for Dock version 1.8 (1040.42) to /Users/macbook/Library/Logs/DiagnosticReports/Dock_2012-11-08-225031_maciosdev.crash 12-11-08 22:50:31,875 ReportCrash: Removing excessive log: file://localhost/Users/macbook/Library/Logs/DiagnosticReports/Dock_2012-11-08-224535_maciosdev.crash Then after every (about) 13 seconds, the same set of 4 error messages repeat. I take a look at thé disk0s2 partition, and it is clear to be thé mac os x system partition which starts up as usual. I can still use thé TextEdit, Firefox, etc. to report this problem. However the interaction does slow down quite a lot, which seems to be understandable if the system accesses the said problematic partition every 13 seconds (but for what?). I don't see any suspicious process with "ps -ef" btw. maciosdev:Logs macbook$ df -k Filesystem 1024-blocks Used Available Capacity Mounted on /dev/disk0s2 243498500 85266476 157976024 36% / devfs 112 112 0 100% /dev map -hosts 0 0 0 100% /net map auto_home 0 0 0 100% /home /dev/disk0s4 243909628 219671824 24237804 91% /Volumes/Untitled maciosdev:Logs macbook$ pwd /Users/macbook/Library/Logs maciosdev:Logs macbook$ But I still launch thé Disk tool to verify this partition, again thé tools says it's in good state. My system was 10.7.2. After encountering this strange problem, I updated it to 10.7.5 but the upgrading did not solve thé problem. I tried also "chkdsk" but -bash says this command is not found. Any hints? Thanks a lot. It's driving me crazy!