my ~/.thumbnails is not a directory but a r-r-r file in order to prevent all desktops from creating thumbnails. thunar's thumbnails plugin cause thunar to loop, using 100% cpu time under such condition as it will try on and on to create it's .png files. to reproduce, create a r-r-r .thumbnails file where a r-r-rw directory is expected
Fixed with revision 25229. 2007-03-19 Benedikt Meurer <benny@xfce.org> * thunar/thunar-icon-factory.c: Automatically disable thumbnailing if storing of thumbnails failes because of a fatal error (i.e. broken setup). Bug #3020.