Final Cut Pro and Final Cut Express: File in use error when rendering

Note: This can also affect Final Cut Express. The workaround remains the same.

Spotlight, introduced with Mac OS X 10.4 Tiger, allows you to quickly perform searches for your files, not only by their names, but also by content and context. To do this, Spotlight keeps track of all your files. Every time you add or change a file, Spotlight indexes details about that file's qualities so that you can search for it later. Spotlight does this indexing all the time, while you're using your computer.

Since Spotlight is part of Mac OS X, it's able to do its job in the background, while not slowing things down for you. For instance, Spotlight's indexing should not interfere with demanding multimedia applications like Final Cut Pro, thanks to Mac OS X's multitasking.

Under rare circumstances, Final Cut Pro will report an error like this one while rendering:

This can happen when Final Cut Pro is creating render files in a folder that Spotlight indexes. But there's no need to worry. Just Click OK, and you can proceed with rendering normally. This will not happen when capturing.

This can happen because of the way that Final Cut Pro caches data while rendering, not because of any issue with Spotlight.

To prevent this from happening, you can tell Spotlight not to index the Render Files folder in your Scratch Disk:

1. From the Apple menu, choose System Preferences.
2. From the View menu, choose Spotlight.
3. Click the Privacy tab to reveal the areas that Spotlight will not index.
4. In the Finder, open your "Final Cut Pro Documents" folder.
5. Drag the Render Files folder into Spotlight's list, as shown here:

You don't need to add the other Final Cut Pro folders. In fact, it can be very handy to have Spotlight keep track of your captured clips. This makes it a breeze to find clips from any project.

This document will be updated as more information becomes available.