Flock creates and edits several files in the Flock profile folder that control some features such as the feed reader or history search. In a situation where the hard drive is full, Flock cannot edit and save these files. You may find that other application have difficulty running when you have a full hard drive, and it is likely due to similar reasons.
We would suggest that you free up some space on your hard drive in order to use Flock's features to the fullest.
