iMovie: Tips to improve performance

This article has been archived and is no longer updated by Apple.

Try some of these tips to improve the time it takes iMovie to open, if iMovie is slow to respond to clicking or dragging, or if video or audio in the playback window is jumpy.

Install the latest software

Periodically, Apple releases updates to iMovie, QuickTime, and the Mac OS. Make sure you've installed the latest versions of this software. The Software Update feature in Mac OS X makes downloading and installing the latest updates a snap. Of course, the latest version of QuickTime is always available from the QuickTime website.

Make sure your computer meets the system requirements

Each version of iMovie has different requirements. Make sure your computer is able to take advantage of iMovie's features.

Only render one clip at a time

Rendering clips takes a lot of processing power. If iMovie seems unresponsive, consider waiting until a clip is finished rendering before continuing or rendering another clip. You could also render clips in small batches to improve responsiveness.

Change playback quality

If you are using iMovie 4 or later, consider changing the playback quality setting in iMovie preferences.

Note: If you are using an older computer, try turning off the option "Keep playhead centered during playback" in the playback pane of iMovie preferences by following these steps:

  1. In iMovie choose iMovie>Preferences.
  2. Select the playback pane.
  3. Deselect the "Keep playhead centered during playback" checkbox.

Turn off Audio Waveforms

If you are using iMovie HD 5 or later, consider turning off "Show Audio Waveforms" from the View menu to free up processing power.

Don't store your project in a folder that uses FileVault

If you are using Mac OS X 10.3 or later, make sure the project you are working on isn't saved in a folder that's protected by FileVault.

Quit unused applications and users

Quit any open applications you're not using. If Fast User Switching is on, consider logging out other users.

Check the disk

Open Disk First Aid. Check the startup disk, and the disk where the project is saved.

Use Disk Utility to Repair Permissions on the startup disk.

Check for plug-ins

Check to see if there are any plug-ins in this directory: ~/Library/iMovie/. If so, remove them. Reopen iMovie and see if performance is improved. If this resolves the issue, contact the plug-in's developer for more information.

Check also for non-Apple plug-ins in /Library/QuickTime/ and ~/Library/QuickTime/ . Try moving any non-Apple items out of this folder and relaunch iMovie. Some older third party QuickTime plug-ins may interfere with iMovie operation. If this resolves the issue, check with the plug-in manufacturer to see if an update to the plug-in is available.

Copy the project to the computer's hard disk

If your project is saved on an external hard drive, try copying the project folder to the computer's hard disk (if there is room) and open it from there. See if this improves performance.

Rebuild the project

If you are only experiencing the issue in one project, consider rebuilding it.

Defragment the disk

If you have access to a disk defragmenting utility, consider defragmenting the drive where the project is located.

Project length

  • If you are only experiencing the issue in one project, consider rebuilding it.
  • The longer and more complicated the project, the more RAM, disk space and processor power the project may require. Try splitting lengthy projects into multiple shorter projects if you are using an older Macintosh and notice a degredation in performance with lengthy projects.
  • Using other suggestions in this article (such as changing the playback quality setting) may also make a difference without having to limit your project length.

Working with HD footage

High Definition footage (HDV 720p or 1080i) requires extra CPU performance to play and edit. Make sure your computer meets the system requirements for HD editing ( 1 GHz G4 or faster) if you are attempting to work with HD footage.

Related document

303529: iMovie: How to move clips from one project to another
42964: iMovie: "Disk Responded Slowly" Alert
Published Date: Oct 7, 2016