A. This may occur if you had a project that used quicktime link files such as the ones created by Raylight, and those files pointed to are no longer available. With FCP closed, you might try clearing your FCP preferences.
This article explains how to clear the FCP preferences. Though it is for FCP 4.0 It is still applicable to the lastest FCP. I have pasted the contents below:
Learn how to resolve issues caused by unusable preference files in Final Cut Pro 4.
When troubleshooting Final Cut Pro, one step you can take is to delete the Final Cut Pro preference files. Doing this restores Final Cut Pro to the default settings and behavior. These files contains user preferences for scratch disk settings, capture settings, window layouts, and so forth.
To delete the Final Cut Pro 4 preferences files, do the following:
1. Quit Final Cut Pro 4.
2. Click the Finder icon in the Dock.
3. From the Go menu, choose Go to Folder.
4. Type: ~/Library/Preferences/ Note: The tilde "~" refers to your home directory. For more information see "Mac OS X: Using Your Home Directory".
5. Click Go.
6. Drag the file named "com.apple.FinalCutPro.plist" to the Trash (Figure 1).
7. Double-click the folder named "Final Cut Pro User Data".
8. Drag the file named "Final Cut Pro 4.0 Preferences" to the Trash (see Figure 2).
9. Drag the file named "Final Cut Pro POA Cache" to the Trash (Figure 2).
[Be sure to Empty the Trash]
10. Open Final Cut Pro.
Here is another thread on the subject.