I noticed many “tracker-miner-fs” threads that seem to be running in the background but sadly use a lot of CPU time. They belong to a very useful framework that aims to improve the Ubuntu desktop experience: https://wiki.ubuntu.com/Tracker

At the moment it is not very useful for me so I decided to disable it for the moment:

echo -e "\nHidden=true\n" | sudo tee --append /etc/xdg/autostart/tracker-extract.desktop /etc/xdg/autostart/tracker-miner-apps.desktop /etc/xdg/autostart/tracker-miner-fs.desktop /etc/xdg/autostart/tracker-miner-user-guides.desktop /etc/xdg/autostart/tracker-store.desktop > /dev/null
gsettings set org.freedesktop.Tracker.Miner.Files crawling-interval -2  
gsettings set org.freedesktop.Tracker.Miner.Files enable-monitors false  
tracker reset --hard   

Source: https://askubuntu.com/questions/346211/tracker-store-and-tracker-miner-fs-eating-up-my-cpu-on-every-startup