I have been experiencing this since I started using Claws. I notice that Claws Mail scratches the HDD way too much when it refreshes RSS feeds (or MH folders) with lots (20-50+) of new items. Very noticeable on an older laptop. Still it looks not normal considering the total size of the folder is less than 1Mb. Looks like some optimization of file read/write may be necessary. version 3.17.3git142