How can I recover a project that I optimized? It will not work after the fact. Can I go back in time without the "time machine?"

Question

I'm freaking out here.  Ok, so I've spent an entire school year filming and editing a video for an afterschool program I work for.  I finally completed the project but was having errors every time I tried to export the movie.  I was advised to optimize all the video clips before exporting the movie so it won't be as much of a load on my computer during the export process.  I did that but now files are missing, all the audio and video clips are not lined up correctly, and it won't allow me to edit anything.  Also, I can't even play back the video anymore.  When I press play, I see nothing and hear audio from a completely different project in my library!  I was told to check in the "iMovie Original Movies" in the "Movies" section of my computer to recover the original, unoptimized movie file.  But nothing is there.  Now I'm stuck with a movie I can't do anything with and all the students are depending on this video being completed.  I do not have a "Time Machine" backup, which I'm regretting now more than ever right now.  Does anyone have any suggestions that could help me???  I'm desperate. 

Answer 1

All I can think of at the moment is to use the old standby of deleting the preference file. This can often fix problems with iMovie.
Go to your Home folder <your user name>/Library/Preferences (NOT the Library folder at the top level in Macintosh HD). Similar to Lion, on Mountain Lion (10.8.3), the Home Library folder will be hidden (unlike pre-Lion OS X versions). To access it, click and hold down Go in the Finder menu bar, then press and hold down the Option key on the keyboard - the Library folder will appear in the drop down list. Slide the pointer down to Library and, as you release the pointer, the folder will open in Finder. Now you can navigate to the Preferences folder.
In your user Library/Preferences folder, locate a file named "com.apple.iMovieApp.plist". With iMovie closed, drag this file to the Desktop. When next opened, iMovie will create a fresh preference file with the default settings (this happens in the background as iMovie is loading).
If iMovie now opens and appears to be working properly, you can change the default settings in the menu item "IMovie > Preferences", as desired. Also, it's now safe to drag the old preference file to the Trash. Trashing the file will not harm any existing Events or Projects.
Note that these instructions are for iMovie '11 (the latest version being 9.0.9). For users on earlier versions of iMovie, the preference file has a different but similar name. For example, for iMovie '09 (that's version 8.0.6) the file is named "com.apple.iMovie8.plist". Earlier versions may or may not have a number in the name, for example, "com.apple.iMovie.plist".
John