My iMovie keeps crashing and will not fully load. What do you think is the problem?

Question

What would be the reason why my iMovie keeps crashing and will not fully load?

Answer 1

I don't know what version of iMovie you are using, nor the Mac OS X version (that's always helpful when posting questions).
However, usually when iMovie has the type of problem you mention, it's advisable to firstly trash the preference file. Here's how to go about it for iMovie '11 on Mountain Lion (similar methods apply for other versions):
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 (currently version 9.0.9). For users on earlier versions, 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"
If this doesn't fix the problem with iMovie crashing, please come back as I have another possible solution to offer.
John