for Ubuntu 11.10 (Oneiric) + Unity (3D)
[Adapted from Alin Andrei (answer).]
UPDATED: Safer method of stop, erase, re-start (for Zeitgeist)
step 1. get the tools
sudo add-apt-repository ppa:zeitgeist/ppa
sudo apt-get update
sudo apt-get install activity-log-manager
step 2. set files/directory activity to ignore.
'Activity Log Manager' >> Files >> Prevent logging files :
(Select folder) /home/$username/Private [Add] - private folders
(Select folder) /home/$username/install/image [Add] - Ubuntu .ISO files
(Close)
step 3. clear ALL history [safe method]
zeitgeist-daemon --quit
ls -l ~/.local/share/zeitgeist/
sudo rm ~/.local/share/zeitgeist/activity.sqlite.bck (if present)
sudo rm ~/.local/share/zeitgeist/activity.sqlite-journal (if present)
sudo rm ~/.local/share/zeitgeist/activity.sqlite
step 4. restart Zeitgeist [safe method]
zeitgeist-daemon &
( The ampersand '&' allows process to run in background. )