I'm using PCmanFM with about a dozen tabs open, moving images and files from one directory to the other. Deleting a lot of photos. Different things happen, like hiccups, more than usual.  But some rather bigger than usual bumps than ever experienced before. On HP Pavillion lappy.
   1.  Last night the system was suddenly overtaken by hundreds of instances of PCmanFM opening, way faster than I could ever close them.  This was finally resolved after five minutes by rebooting. 
   2.  Not always detecting the USB connection, until it is retried a few times in different slots.
   3.  Clicking on some folders just suddenly crashes the window. No particular pattern to this crashing.
   4.  After last crash, the trashcan and seamonkey icons vanished from desktop icons.  When I tried to replace them, the message said that seamonkey icon was already there.  I rebooted box, and this resolved the missing icons.
   5.  sometimes I cannot access files on the USB sticks, which I can see, but files will not show up, even when mounted.  Or sometimes, when selecting files from a program, I cannot see the USB sticks at all, even though PCmanFM shows them.