PCManFM "Not Authorized" when mounting internal drive

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https://bbs.archlinux.org – Hello all,I recently installed Arch and was setting up PCManFM, but I have run into a few problems. At first, I had no icons, and couldn't see the other internal drives on my system, but thanks to the PCManFM wiki page, I managed to sort those problems out. However, now I am left with the problem where, if I try to open one of the other partitions, PCManFM spawns an error dialog that just says this:"Not authorized to perform operation"To summarize what I have done / tried:I am using SLiM as my login manager, and have the following as my login_cmd/exec ck-launch-session dbus-laun (HowTos)