Media Express not releasing captures for transcode

Setting up a workflow with Decklink card capturing and it's output folder watched by Sorenson for transcode. The captured file appears locked until Media Express is shut down, then Sorenson can pick up for transcode. Is there a way that the captured file can be unlocked without shutting down Media Express? would prefer to leave both applications running to maintain a constant workflow, otherwise I'll have to run a script to cut out of Media Express output into separate Sorenson watch folder
Help would be much appreciated