In Windows Media Player 12 on Windows 7 files folders that I add to the Music and Videos libraries, other that the built-in C:\Users\Username\Music and C:\Users\Username\Videos folders, disappear from the music and video collections in both WMP and the Media Streaming Service (as seen from my XBOX 360), between reboots. So for example I've added a folder called 'C:\Users\Username\Podcasts' to my Video library, expecting the videos podcasts it contains to show up under videos in WMP and on the XBOX. Unfortuantely, the video files only appear on the XBOX interface when I've loaded WMP on my PC and allowed it to rescan my libraries.
The only way that I've so far found for these items to be restored is to start WMP. It then rescans the Music and Video libraries and re-adds the missing files to the list. Often when doing this files are added to the list twice.
This was a problem in the release candidate (build 7100) and, as it turns out, the final version of Windows 7.
Is this a known bug? Is there a workaround? Has anyone else experienced the same problem?