Did the usual stuff – disk repair, disk verify (caught some small things).
That fixed the disk full messages.

Then the client told me – oh, by the way, Safari doesn’t open.

Tailing the system log in console still revealed issues.

14/04/09 09:07:43 com.apple.launchctl.System[2] could not fetch history: Cannot allocate memory
14/04/09 09:07:43 com.apple.launchctl.System[2] BootCacheControl: could not stop cache/fetch history: Cannot allocate memory

A quick google of that error showed it was caused by…. Wacom drivers.

While Wacom have updated drivers for other tablets, the client uses a Bamboo, which hasn’t had driver updates since 2007.

Checking the logs while opening Safari revealed that it was trying to open a non-existent file called com.pentablet.defaults.xml

On the off chance that this would work, I created a blank file in terminal.

Terminal
sudo su
[enter in your password]
cd /Library/Preferences
ls -al com.pentablet.defaults.xml

If (and ONLY if) no file is found, do this:

echo > com.pentablet.defaults.xml
exit
exit

Safari will open again.

Hopefully Wacom will release newer less buggy drivers sometime soon.