The first time you open Final Cut Pro 5, a dialog opens, prompting you to set the location for the Primary Scratch Disk. Your scratch disk setting determines the location for video files used by Final Cut Pro, such as video that you capture and video that Final Cut renders. The default location is ~/Documents/Final Cut Pro Documents.
The dialog looks like this:
You can use the Primary Scratch Disk pop-up menu to choose a hard drive or a folder as your scratch disk location. However, there are two situations in which the dialog may act unexpectedly:
Once Final Cut Pro opens, you can work around these issues by choosing Final Cut Pro > System Settings and then clicking the Scratch Disks tab. You can then change the settings to your liking.
For more information on setting Scratch Disks and other initial settings, refer to the Final Cut Pro User Manual, available under the Final Cut Pro Help menu.
This document will be updated as more information becomes available.