When you double-clicking an iMovie project file in Mac OS 9, an alert box with this message appears:
By default, iMovie 2 for Mac OS 9 Mac OS X are both installed on the hard disk.
Since iMovie 2 for Mac OS X is more recent, the Mac OS 9 Finder tries to open the iMovie file using iMovie 2 for OS X. This version of iMovie is
not designed to work with Mac OS 9. If you try to open the file using iMovie 2 for Mac OS X this alert box appears.
To open the file in iMovie 2 using Mac OS 9, do one of the following: