Find why it drips, then fix that
Gravity drain blocked, trap reversed, pump dead, pan cracked, or ice melt from a dirty coil. The repair is the cause, not a towel on the floor. A 20-minute-into-cool drip is usually the pipe. Immediate water on start can be a cracked pan or a slope.
Cassettes often fail at the condensate pump. Wall splits fail at the trap and the slime line. Opening gypsum is only if the path needs it and you approve the cut.
