Why is my coffee maker overflowing or backing up with water and coffee?

Clogging and backing up can occur from using too finely ground coffee, using two or more paper filters, using the gold-tone filter with a paper filter simultaneously, or not properly cleaning coffee grounds from the gold-tone filter. Ensure you use only the Cuisinart Gold-Tone Commercial Style Filter or standard cone-shaped paper filter, but not both together. (Page 1 — Operating Notice)