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100% CPU usage caused by syslogd (Leopard)

Over the last few days I experienced a strange bug that didn’t go away even after several times of rebooting — a process called syslogd used up to 100 percent of one CPU, which means up to 50% of my computer’s processing power.

After some research, I found the following solution:

Fire up Terminal and execute the following commands (enter administrator password when asked):

sudo launchctl stop
sudo rm /var/log/asl.db
sudo launchctl start

What do these commands do? First of all, we stop the syslogd process. The second line removes a database file which causes the whole dilemma (don’t worry, it’ll be re-created afterwards), the third line starts the previously stopped process again.

Now reboot your Mac and everything should be fine!

Via Smarticus‘s comments.

Trackbacks & Pingbacks

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  1. Quote

    Great post.. I’ve been using this for a while (albeit just the first line to stop syslogd) whenever my CPU got all riled up. Hopefully Apple addresses this in 10.5.2.

  2. Quote

    Thank you! I had the same problem

  3. Quote

    Great tip. Helped also on my iMac 24″. Now tested few days and all is still ok. Thanks!

  4. Quote

    This is the most useful page of the internet for me this month !! ;-)

    I was googling for ages to find what was causing this syslogd havoc… Now I will google with my quiet cpu to find what made this al.db mess.

    Thanks !

  5. Quote


    just had the same problem on my MacBookPro. Now, everything is back to normal. Thanks Big Time !!!

  6. Quote
    t3chm@n said March 28, 2008, 4:11 pm:

    I also managed to benefit from this post!


    I have posted a comment in the Apple support forums to add a sticky to this post so that others may benefit from this until Apple issues a fix for the issue.

  7. Quote
    Ralph Cormann said March 30, 2008, 5:17 pm:


    Ich “hatte” das gleiche Problem mit meinem IMAC Intel Core 2 Duo 2,4 GHz.
    Nachdem ich alles wie hier beschrieben eingegeben hatte und den Computer neugestartet habe war das Problem tatsächlich gelöst. Jetzt macht das Arbeiten wieder Spass !!!
    Vielen dank für die Info hier.

  8. Quote
    nikster said April 11, 2008, 1:59 am:

    thanks for the info, much appreciated. problem solved.

    this happened to me on 10.5.2, so I am hoping it will be fixed in 10.5.3…

  9. Quote

    I’m not normally motivated to respond to advice like this online, but this is perhaps the single best time/money saver I’ve experienced in a long while. I was seriously afraid I would have to reinstall my programs, send in the computer for repair, whatever.

    syslogd is now behaving like it should with lots of programs open.

    Vielen Dank fuer die Info!!!!!

  10. Quote

    Thanks for all your kind comments — It’s always nice to receive feedback!

  11. Quote

    I talked to Applecare for an hour this afternoon because syslogd was hogging my CPU. Nil result.
    I’ve just implemented your fix and hey presto – solved. Thanks Julian

  12. Quote

    Thanks a load!

  13. Quote
    freno said May 14, 2008, 2:34 pm:

    You may also want to try and edit the file with the command line tool PlistBuddy to calm down your Mac!

    Using PlistBuddy to customize syslogd


  14. Quote

    Ohhh thank you so much for posting this!! I think lots of people must have looked this up, this problem hit me today and I was freaked out trying to do sudo killall syslogd and nothing happens… then your post came up as the first result from Googling “mac os x cpu usage syslogd”!!

    Only if I can dig this… actually I will!!

    Thanks so much!!

  15. Quote
    DeeJan said June 17, 2008, 8:13 am:

    I also had to delete /var/log/system.log:

    sudo launchctl stop
    sudo rm /var/log/asl.db
    sudo launchctl start

    100% CPU again!

    sudo launchctl stop
    sudo rm /var/log/system.log
    sudo touch /var/log/system.log
    sudo launchctl start

    syslogd is idling normally!

  16. Quote
    Christoph said June 19, 2008, 7:28 pm:

    Same here (today I have installed some apple updates).

    Deleted system.log and now syslogd is idling normally!

    Thanks for the help!!!

  17. Quote

    Hat mein Problem auch gelöst, war allerdings 5 Minuten später wieder da… :o (

  18. Quote

    i have the same problem but i couldn’t use sudo commands, since it asks for password , i don’t have a password in my system and i am the only user, i just hit on enter and it does nothing. help me please

  19. Quote

    @halit korpe: of course you have a password. it is the one you chose when you started your mac the first time. if you forgot it use the system-dvds to restore the password.

  20. Quote

    good work. thank you.

    reminds me of the old “zip worm” that cam eon zip drives back in about 96-97. crunch crook.

  21. Quote

    Thank you. I have an old eMac and this trouble was seriously slowing down my computer. Now I don’t have to think on buying a new iMac, so… thanks? :D

  22. Quote

    Thanks for this, dam syslogd was driving me mad, thought there was not reason for my macbook pro running of such high fan speeds all the time.

    Though the process only works for me if I stop the syslogd…. will that be bad for my system?
    And is there any way to stop it permanently?

  23. Quote

    Hi Eduardo,

    it’s okay to stop syslogd temporarily, but since it is an essential part of the system it’s not a good idea to stop it permanently—you don’t want to prevent several services from the system’s core from running.


  24. Quote

    It is such a glaring flaw in OSX. One day it simply rendered my computer unusable and even the 10.5.5 update preserved this crap syslogd. Your commands worked beautifully – thanks! Now, Apple is really turning into Microsoft at its worst: there used to be registry and now I am supposed to fix OSX by typing some obscure commands.
    I guess the time when computers can actually be relied upon is still pretty far off…

  25. Quote

    I’m so glad i got my computer back! I was so frustrated at how my imac G5 was so sluggish, and was considering buying a new imac.

    Thanks so much!

  26. Quote

    Why is it that the best source of information like is always OUTSIDE the Apple website. Woke up this morning to my MacBook Pro fans spinning like crazy, saw the CPU usage of SyslogD, and did a web search, found this page, problem solved.

    Would be curious to know what exactly is happening that causes this, is the file corrupt or something?

    Anyway, thanks for the tip!

  27. Quote

    Hi Tim,

    that’s correct, syslogd gets the hiccups when its database file is corrupted. Delete it and syslogd starts over, no problem remaining. :-)


  28. Quote

    This Problem returns frequently on my eMac.
    I can solve it with the following commands by Julian and DeeJan.
    Is it posiible to buidl a script that I can doubleclick, so that i don’t have to type it manually every time?
    Thank you, Felix.

    DeeJan said June 17, 2008, 8:13 am:

    I also had to delete /var/log/system.log:

    sudo launchctl stop
    sudo rm /var/log/asl.db
    sudo launchctl start

    100% CPU again!

    sudo launchctl stop
    sudo rm /var/log/system.log
    sudo touch /var/log/system.log
    sudo launchctl start

    syslogd is idling normally!

  29. Quote

    Thankyou! After following these instructions my Mac finally started responding after this happened a few days ago – I suppose this could be put into a cron script to make this problem fix itself before it happens?

  30. Quote

    I’m glad i came across this article, a very positive read indeed

  31. Quote

    100% CPU usage caused by kernel_task can you help plz (Leopard)
    macbook air 10.5.6
    specially when running skype video conference

  32. Quote
    Robot said May 11, 2009, 3:48 am:

    Guys, I’ve been trying to solve this issue for months now. I’ve ready everything I could find on the internet, and tried everything and nothing helps. Sure it’ll stop the process but then a few hours later its back again. Has anyone found a permanent solution for this? I tried getting help at Apple store but they are such Apple Nazis that they refuse to admit there is even a syslog issue. Fucking lame.

  33. Quote
    Wesley Branch said December 7, 2010, 1:54 pm:

    @halit korpe: of course you have a password. it is the one you chose when you started your mac the first time. if you forgot it use the system-dvds to restore the password.

    I am also having this problem… I am a single user – so I set up no password… I just hit “return”

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