I'm using version 2012 Movie Maker.    The Input video clips were taken on iphone4 and iPad and are .mov files, and come from various folders located on a NAS drive.

When the project file is re-opened, Movie Maker appears to locate only the first clip.    All subsequent clips show the yellow triangle with exclamation point.    I can readily "fix" this.     The next time the project file is opened, the same thing happens again.    And the next time, etc.!

I tried converting the .mov files to .wmv files - however exactly the same thing happens.

In summary, Movie Make knows the correct folder and filename for each clip, but apparently does not find the clips (other than the first).

The problem does NOT occur if the source files are located on a locally attached drive.

What is causing the problem when source files are on the NAS (a Synology box)?