I am using the Windows version 2.8.1. When saving a *.mp4 or *.mkv file, the program adds "_edit" to the filename when saving into the source folder. It does not add "_edit" when saving a *.MP4 or *.MKV file. It does detect that a file already exists and prompts to either overwrite or change the filename. In Windows, filenames are not case sensitive, so saving a file named aaa.mp4 will overwrite an existing aaa.MP4 file. Suggest that in Windows "_edit" should be appended to the saved filename regardless of the case of the file extension.