Before converting DRM video files from iTunes Store, you need to set iTunes not remembering playback position manually. Here’re the steps to follow:
1. Launch iTunes, and switch to “Movies” under LIBRARY.
2. Select the videos you’d like to convert, right click on them, and select “Get Info”.
3. Switch to “Options” tab, find “Remember playback position” and uncheck it.
NOTE: Conversion of DRM-restricted files requires assistance from iTunes. DO NOT turn off iTunes until the conversion is completed. Don’t let your computer sleep during conversion, or you’ll get uncompleted files.