For the past couple of days, my old Macbook Pro (Core 2 Duo, 10.8.2) has had 100% cpu usage, with Finder using 100%+ CPU according to Activity Monitor. Finder being the base for everything dealing with file access, this caused file access to take forever. This was highly annoying because I keep a lot of apps open at the same time in different desktops, always switching back and forth between tasks at work. Not efficient, but it gets the job done, except for when the system is being bogged down by a mystery process.
I finally got a look at it today. OK so maybe there is part of Finder that has gone out of control. I reboot the Mac without letting it restart apps on login. My Mac becomes very quiet and the fans slow down while I let it sit at the login prompt. I log in, and the fans whir back up to speed and CPU immediately jumps up to 100%. Something running on here was very persistent. But I was more persistent.
I took another look at the Activity Monitor. Every 5 seconds, syslog would pop to the top and drop back down. From my UNIX background, I thought to look at the system log in /var/log. There it is, a very large log file. Syslog has been busy. Lines and lines of
com.apple.launchd.peruser.501 (com.apple.assistantd): Job appears to have crashed: Trace/BPT trap: 5
ReportCrash: Saved crash report for assistantd version 25.4 to /Users/eoporto/Library/Logs/DiagnosticReports/assistantd_2013-03-12-091455_Ernests-MacBook-Pro.crash
Assistantd was having some trouble. On top of that, it was logging like crazy, writing constantly, for days – something that could destroy an SSD drive. All of the forums said you just delete ~/Library/Preferences/com.apple.assistant.plist and reboot. I take a look at the file, it looks like gibberish, I delete it, and reboot. (I know, I should have made a copy!) No dice. Assistantd is the process that deals with “Dictation and Speech”. So I try to shut that off, and now the System Preferences panel is stuck, neither being on or turning off. Dictation has frozen up the system and response time gets worse. I reboot, and the problem is still there. Dictation and Speech is still trying to run and crashing, multiple times per second, and I can’t stop this cycle of pain.
Finally, after many boards and blogs, I come across someone advertising their Dictation switching program, DictationSwitcher. It has the ability to switch languages on the fly, and turn dictation on and off, without involving the preferences pane.
I turned off dictation using DictationSwitcher, and reboot.
The system comes up noiseless and stays noiseless, even after login. DictationSwitcher created its own plist file when I turned off dictation, and on reboot, the system did not try to restart assistantd. And finally I can get back to work. And I will keep DictationSwitcher on hand in case my Mac ever randomly decides to go nuts again. Thank you René Fouquet!