FCP 7: Understanding Scratch Disks

Posted on by Larry

[This article was first published in the November, 2006, issue of
Larry’s Final Cut Pro Newsletter. Updated December 2010. Click here to subscribe.]
Bill Darst started me thinking about Scratch Disks again when he asked:

Because I have 5 external drives upon which I have put 6 two hour programs, I am wondering why can’t FCP keep track of which Scratch disks have which programs (project files) . Every time I have to open one of the 15 projects, I always have to go and assign the disk it was assigned to. Sometimes I just want to check or add an item, and may open and close 5 or 6 programs, but again, I always have to remember to assign the scratch disk once again to each project file I open. Would it be that hard to create a small program that remembers where that project file was stored and just assume you would always want to use the same storage area each time you open it up?

Larry replies: Bill, Scratch Disks are system-specific, not project-specific. However, FCP is designed to do what you are asking without you having to change a thing. The key is in understanding how scratch disks work.

Scratch disks store the media that you capture from video tape, as well as render files and other technical files that Final Cut needs. However, and this is the important part, media files are ALWAYS stored in a folder named after your project.

Here’s an example. At the top level of my media drive, I created a folder called “Final Cut Pro Documents” (the exact spelling and capitalization are important). Then, I pointed my Scratch Disks to this folder (Final Cut Pro > System Settings > Scratch Disks).

Inside this folder, Final Cut automatically created a series of six folders. All media captured from video tape is stored in the Capture Scratch folder. However, and more important, it is ALWAYS stored in a folder insdie Captuer Scratch that is named after the currently active project. In this case, I have four different projects all stored in the same capture scratch folder.

So, Bill, in your case, you would create a “Final Cut Pro Documents” folder on each of your five media drives.

Then, in the Final Cut Pro > System Settings > Scratch Disk tab, set a scratch disk on each of your five disks by clicking the Set button and navigating to the Final Cut Pro Documents folder. Do this for every media hard drive you have. Then, make sure all four checkboxes are checked for each line.

These checkboxes tell Final Cut that it can record media on any of the five media drives. Best of all, Final Cut uses what’s called “load balancing,” which means that it always records media to the drive that is the emptiest. This helps spread your media across all five disks and reduces the wear-and-tear on any single drive.

This system gives you the greatest flexibility, without requiring you to reset scratch disks for each project. As you switch from one project to another in Final Cut, FCP will, behind the scenes, automatically switch media folders so that any new render files or any new captured media are always stored in the folder named after the currently active project. (An active project is the front-most tab in the Browser; it has a light gray tab.)

Best of all, when it comes time to delete a project, the Render Manager can easily delete all unneeded render files because it tracks all render files on all current scratch disks. To delete captured media, go into the Capture Scratch folder and simply delete the folder named after the project you want to delete.

Easy, simple and straight-forward.

Here are two articles I’ve written that can help you learn more:


Tim Spauling writes in with an additonal comment:

I read what you wrote and generally agree. But I think the intent of the writer’s question was a little different.


Since he has several external Firewire drives, I assume he is probably like me and often needs to switch from project to project. Often times a project gets shelved or set a side, while I work on another project. In order to make quick changes or hand off the project to someone else, all elements of that project need to stay in one place.


Side note: Danger! Danger!… I noticed the way FCP numbers render files the same on drives, so if you don’t have everything pointed in the right place, weird things can show up on the screen (Have different names for all your drives. [This means that using Reconnect files to] auto-find render files can cause some serious feakiness, always double check timelines before saving!).


I think what we are looking for is a program or function that will encode into the project file which drives are set for a project and set up your scratch disc the same way they were set for each project. Having to constantly change scratch disc around and remembering to do it every time one needs to change projects is a royal pain!


Project Profiles… Now wouldn’t that be cool!

Larry replies: Tim, you make some good points. Project profiles is something that FCP does not currently support. Thanks for writing!


Greta Wing Miller contributes one more thought on this subject:

I also use at least 3 different external media discs: right now I am simultaneously working on 3 different projects. The media for each of them is captured to its respective FCP Documents folder on its respective scratch disc. The way I get around having to reset each time, is that, once I capture all the media to the correct drive, that drive has to be powered up to edit, of course, but I point the scratch disc pref to an FCP Docs folder on my second (250gb) internal drive (G5). That way, all the render files go on the internal drive, and I never have to reset the pref–unless I have to capture more media.


Thanks so much for everything,

Larry replies: Greta, this is a good work-around. Thanks for sharing it.


Vincent writes:

I bought your Final Cut Pro 6 – Essential Editing DVD the other day and it is excellent. However, I would like for you to clarify the physical task and take me through it, that is, the procedure to follow your instruction when you say, “point your Scratch Disk to Final Cut Pro Documents folder on your 2nd. Drive”. How should this be done?. I understand the importance of this folder.

Larry replies: Thanks for the kind words, Vincent!

Scratch Disks are set in the following way:

Never store media on your boot disk.

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