I've been using the Dyson Purifier Cool Air Purifier (TP07) for two years and have been replacing the filter annually. Recently, though, I’ve noticed a sour smell coming from the air. I’ve tried brushing off the dust from both the replaceable filter and the catalytic filter, but the smell persists.

After running a few tests, I believe the filter might be the source of the odor:

1. With both filters (catalytic and replaceable) in place - there's a sour smell.
2. When I remove the replaceable filter, leaving only the catalytic filter - smell is less noticeable.
3. With both filters removed - there's no smell at all.

I've looked for solutions online and it seems this is a common issue for many others. Unfortunately, Dyson staff have been unable to resolve it.

Removing both filters might actually defeats the purpose of filter and it becomes a fan instead.

If anyone knows how to fix this, please share your advice!