"When importing footage into the program, a user can either choose to Capture Video (from camera, scanner or other device) or Import into Collections to import existing video files into the user's collections. The accepted formats for import are .WMV/.ASF, .MPG (MPEG-1), .AVI (DV-AVI), .WMA, .WAV, and .MP3. Additionally, the Windows Vista Home Premium and Ultimate editions of Movie Maker support importing MPEG-2 Program streams and DVR-MS formats. [6] Import of other container formats such as MP4/3GP, FLV and MOV ,MIDI, AIFF, AAC and SWF is not supported." - http://en.wikipedia.org/wiki/Windows_Movie_Maker
Så om den inte kan importera filen är det bara att konvertera omden till något av ovannämda.
