PCManFM stopped working

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http://askubuntu.com – PCmanFM is not accessible. My lubuntu desktop has become unusable: the normal desktop, handled (i think) by pcmanfm was replaced by an empty one, while pcmanfm became unstable: first used 100% of cpu, then would not be accessible at all, despite the fact that it is runing. I have installed LXDE beside lubuntu-desktop and for a while in lxde all looked normal, but after several logins/logouts the same issues appeared in lxde session too so i purged and reinstalled both pcmanfm and openbox (which meant reinstalling lubuntu-desktop and lxde) now i have pcmanfm 0.9.10 it didn't help clicking (HowTos)