About my situation, we have FCP X 10.0.8
The files are already on the Xsan in ProRes 422 and we just link to the file in some folders. No copy.
When both are on the san with Add San Location we create an Events and import files without copying.
In the window of importation we’ve got the video and sound from the file. But after the importation in the Events window we see it in red and MISSING FILES on it and no sounds on audio clips.
But when we do an Events on the HD it works, or the files on HD and Events on the san , it works too.
I clean reinstall FCPX, same thing.