final cut express voiceover problem

I am video editing on a MacBook Pro mid 2014 running Sierra, the book has a 2.8ghz core i7 and 16gb @1600mhz DDR3. My scratch disc is a Lacie external 2TB drive with 1.72TB free USB connected. This has always worked fine. Today as i try to do a voice over a bubble comes up saying "specified capture destination file already exists" and will not allow me to do a voiceover anywhere in my sequence, even though I did a voiceover twenty minutes ago. During my editing today the external drive somehow came unplugged from my laptop and a warning came up that it had been disconnected without "unmounting". I plugged it back in, problem then started. I shut Final cut down and rebooted...same problem. Shut the whole computer and external drive down and same problem when i rebooted everything. During the problem as I tried to continue to edit, a bubble came up saying a number of video files had gone off line. I was easily able to reconnect them once the external drive was reconnected. Do I need to somehow reconnect the audio files? Any audio attached to video is still on the project and any previous voiceovers are also still present. Any ideas? Thanks