There are a variety of files and folders that Final Cut creates automatically. Here's what they are, where they are stored and what they do.

All these automatically created folders and files are related to choices you make when you set your Scratch Disk, using Final Cut Pro HD > System Settings

Project File. This is the file that contains all your clips and sequences. You control what it is named and where it is stored, but, since it is created by Final Cut, I thought I would mention it here.

When you set your Scratch Disks, Final Cut creates six folders:

• Capture scratch
• Render files
• Audio render files
• Waveform cache
• Thumbnail cache
• Autosave Vault

The first three files are always stored together, based upon how you set your scratch disks at the top of this dialog.

The second three files are set based upon your selections in the middle of this dialog. Their default locations is inside the Final Cut Pro documents folder inside your User folder. While all the files these three create a small, so their ultimate location doesn't make a real difference, I tend to locate them in the same location as the first three files.

In all cases, I create a folder on my second hard drive, called FCP Media, and point all of these folders to that one location. That makes storing, locating and removing all files related to a single project simple and quick. Here's an article that describes this organization process.

But, I digress. Let's take a look at the files each of these folders contains.

These first three folders all create files that use the same icon, and all three folders are stored together.

Capture scratch. This contains all the media files you capture with Final Cut. Audio and video. They are all stored as QuickTime files.

Render files. These files are created whenever you render a video transition or effect. They, too, are stored as QuickTime files. The letters "FIN" in the file name, indicate they are rendered at the highest possible quality. Using other render quality settings will alter the file name.

Audio render files. These files are created whenever Final Cut renders an audio effect, or creates a mix-down. Mix-downs occur whenever your audio tracks exceed the real-time track limit set in User Preferences. The default setting is 8 tracks.

These next three folders all create files that use the same icon, but different from the first three folders. While these three folders are most often stored together, each can be stored separately. I make a point to set all six files to the same place: the FCP Media folder, which I create on my second hard drive.

Waveform cache. These files contain the images of your audio waveforms that are displayed in the audio tracks of the Timeline. It's a good habit to turn off the display of your waveforms (type Option+Command+W), unless you are specifically editing audio clips where seeing the actual waveform on the Timeline helps you decide where to place the edit point. You'll get faster performance from your computer that way.

Thumbnail cache. These files contain the small images of your video clips that are displayed in the Timeline and the Browser.

Autosave Vault. These files contain backup copies of your project files so that, in the event of a crash, you can recover your project more quickly. You set how often these backups are created in Final Cut Pro HD > User Preferences. I have my Autosave Vault set to 15 minutes.

Generally, I don't worry about the files in the AutoSave Vault, Thumbnail Cache or Waveform Cache folders. The files are small and tend not to get in the way. However, when I am done with a project, I will always use Tools > Render Managerto get rid of render files and delete all media files using the Finder.

Now you know.