If your machine does not run because of this ,Sometimes the filter forms a white deposit on the mesh blocking it a bit, try running time dry prog with no filter, if runs get new filter. if its a vented dryer check outlet through wall, If its a condenser check condenser as well. Be aware that if your machine runs ok but puts up the clean filter at the end of every cycle this is purely a reminder by the manufacturer I have seen this on some Siemens and Bosch machines. Cheers
Kenjo
July 2013