Try to follow instructions in the User's Guide, page 8, and clean the main (macrofilter) and microfilter (comes in 2 parts). Be careful when placing them back, it has to fit tight. Booklet does not give clear instruction as to which marks to align...
I had the same filter problem 2 days ago and today again. Now I am waiting to see how long today's cleaning will last.
Miša, February 2010