I've noticed that footage files in my Adobe After effects projects (such as a video file) that is included on the composition I send to the AME to render, is locked until I then close AME.
I can understand that AME needs to lock the file while it renders. But once the render is complete, this lock should be released.
This can be reproduced by creating a new After effects project, adding a composition from footage and choose a video. Render that composition in AME and once it is completed, attempt to rename the video in windows explorer. You can't, not until you close AME.