Please, excuse my bad english language because I am french, but there in no french forum about PhotoMechanic.
All is OK for my photos with PM. My problem is  I have many doublons  in the navigator :
 15 « desktop »,  3 « Applications », 3 « home »   etc… 
I don't know when they appears, I work rather with the part « favorite ». Really too much !!!!
I am not able to reset this column. 
Thanks for help me.
Soizic.
IMac Intel X10.5.7  PhotoMechanic 4.6.1