DIAGNOSIS The filter's dense, non-woven material retains water. Standard drying methods are insufficient.
FIX Use the correct washing and drying procedure. 1. Remove the filter (top of bin for post-motor, inside the ball for pre-motor). 2. Rinse under cold tap water only. Rotate and gently squeeze the filter until the water runs clear. 3. Do not wring, twist, or use soap. 4. Press the filter between palms to remove excess water. 5. Place it vertically on a towel in a warm, well-ventilated area. Do not apply direct heat. Minimum dry time is 24 hours.
IF THAT DIDN'T WORK You may have the older, denser filter variant. After squeezing, roll the filter in a dry, absorbent towel and press firmly to wick out more moisture before the final air-dry.
HEADS UP Running the vacuum with a damp filter is the primary cause of low suction and motor overheating. Verify the filter is 100% dry by weight and touch. When in doubt, wait another 12 hours.