Unknown volume??

You are trying to save your file to a hard drive that is not being recognised by the Mac operating system for some reason.

Try saving the file on another hard drive until you can establish why you are seeing this error message.

Run Disk Utility on the disk in question. Select your disk at the left side of the Disk Utility window, then click "Repair Disk" at bottom right.

Post any error messages it produces, here.

Do you have a "/" in the volume name?

Which disk is it? If this is your start up disk, you will not be able to repair it whilst the computer is running from it.

You can try the "Verify Disk" button, it will tell you what is wrong but not fix it. You have to start from your Mac OS X installer disk to do that.

I get this error when saving a project to an Xsan volume when someone else on the network has logged out or shut the machine down and not ejected the volumes.

My workaround is just save a copy to the desktop and then drop that into the volume you want to in the Finder.

Seems FCP gets its knickers in a twist at times.