In past versions of Mac OS X, system and process log messages were received and managed by "syslogd" and the "syslog" utility. Under Mac OS X 10.5.6 Apple has included a new set of log functions in the "ASL" logging method and API. These new functions are run by the "aslmanager" process, which is invoked immediately after syslogd runs.
Apple is migrating log management over to using the new ASL logging functions for future versions of OS X, but there appear to be a few bugs in the current versions of the ASL utilities.
Hopefully the bugs in aslmanager will be fixed in future updates.
Fix: Restart log managers after removing asl data
= Open the Terminal application and enter the following two commands to stop the log managers:
sudo launchctl stop com.apple.syslogd
sudo launchctl stop com.apple.aslmanager
Then create a folder on your desktop called "temp" (to store the moved "data store" files), and enter the following command in the Terminal to move the "ASL" data to the new temporary folder:
sudo mv /var/log/asl/* ~/Desktop/temp/
Finally, restart the "syslogd" process with the following command (the aslmanager will be started when needed by syslogd, so it doesnt need to be manually restarted):
sudo launchctl start com.apple.syslogd