[Matt Pankratz]

I had the same issue with getting the “File Error: Illegal Name” when trying to “render all” in Final Cut.

After changing hard drives to where my renders were being saved, cleaning out all my render cache with the render manager, restarting and changing my timeline name, I still got the same error in the middle of my renders.

I then discovered in my Final Cut Pro, System Settings that somehow the checkbox for “Limit Capture/Export File Segment Size” had gotten checked. After unchecking it, the error is gone.