Selena 6556 unable to save project on removable USB media ?

I had moved a project on a USB key previously, and opened it in IDEA.

No modules are loaded, and when going to project settings a dialog pops up saying "could not save project, F:\ not found".

But I can see drive F in explorer, i can browse it too, and cd to it using command line.

Worse thing is the ipr and iws I just opened (on F) were deleted by IDEA !