Answer: The easiest way is to purge old sample data and then recreate the Foxhound database as follows:

• Use the Foxhound Options - Purge sample data feature to speed up the deletion of old sample data.

• Wait until the background purge process has had enough time to increase the amount of free space to the level you want; for example, from 2% to 75%.

  This may take a few hours or even days if you have a lot of data to delete; watch the amount of free space displayed by the Foxhound Options - Purge sample data feature.

• Reinstall Foxhound following these instructions.

  This process will create and reload a new Foxhhound database with just the remaining data and much less free space.

See also...
Foxhound Options - Purge sample data
How do I reinstall Foxhound?
How do I keep the Foxhound database file from growing so large?
How do I keep the Foxhound log file from growing so large?