How to speed up iMovie and make your Mac run faster

Just in a few short years, video has legitimately taken over the internet. As an incredibly versatile and powerful storytelling medium, video is able to grab and hold our attention better than text, audio, or imagery. So no wonder there has been an explosion of tools to help you create the exact look and feel you seek. 

While professional movie editing software costs anywhere between $240 and $450 a year, Apple generously offers its video editing suite iMovie on both iOS and macOS platforms for free.

If you’ve extensively used iMovie in your work, you may have experienced it slow down, lag, or in the worst case scenario — crash. Even if you are not working with large HD files, or using Stabilizing or Rendering features that demand a lot of power, it’s possible for iMovie to come to a standstill. This can be extremely frustrating, especially if you are on a deadline!

Why is iMovie so slow?

If you are wondering what’s causing your Mac to freeze repeatedly when cutting clips or why it’s taking forever to drag and drop things around, look no further than iMovie’s hunger for performance power.

To see how much impact running iMovie has on your Mac, just open up Activity Monitor and inspect the Central Processing Unit (CPU) and Random Access Memory (RAM) levels. While CPU points out the amount of work your Mac can handle and how quickly it can perform a task, RAM affects the processor’s ability to quickly and easily access information.

Buying more RAM is a good idea, but can be costly. Luckily, there are a few other ways to speed up iMovie that can save you money, energy, and time.


Plug your Mac into a power supply

Charging is a simple hack that can give your Mac a noticeable boost! Here’s why it works: the CPU adjusts its speed on the fly in order to balance performance and power consumption. As such, it automatically switches to low power mode when not hooked up to a power adaptor. But when plugged in, CPU doesn't have to concern itself with energy conservation.

If you are not close to a socket or happen to be without a charger, you can manually adjust the Energy Saver preferences to not let macOS put hard disks to sleep, so they wouldn’t spin down and turn off motors while on battery power, thus making iMovie wait longer when it needs to access data.

To change or adjust Energy Saver preferences:

  1. Open System Preferences > Energy Saver > Battery tab.
  2. Uncheck the “Put hard disk to sleep when possible” box.
  3. Uncheck the “Enable Power Nap while on battery power” box.

Delete unwanted folders and cache files

Still finding iMovie slow? Delete some files — a general rule of thumb is to have at least 25 GB of free space on your hard disk to run iMovie smoothly.

Start by deleting iMovie cache files. Cache files are essentially data files that log what you have done. They document changes you make and speed up revival next time you want to work with the same data in iMovie.

To delete unnecessary iMovie cache files:

  1. Close iMovie.
  2. Open a Finder window and select Go from your Mac’s menu bar, then Go to Folder…
  3. Type in ~/Library/Preferences and select Go.
  4. Move the com.apple.iMovie.plist file to the Trash, empty the Trash, then open iMovie again.

Now, move all unwanted cache folders from your Mac to the Trash:

  1. Open a Finder window and select Go > Go to Folder…
  2. Type in ~/Library/Caches and select Go.
  3. Delete the files and folders that are taking up the most space.

In addition, to really trim the fat from your Mac’s storage files, you should delete outdated iMovie folders. If you’ve updated to the latest version of iMovie, and no longer want to use the previous versions, iMovie Projects and iMovie Events folders can be deleted. Also, remove what’s duplicated and no longer needed from your iMovie Shared folder.

Minimize tasks and close other programs

You may have noticed iMovie slowing down if you have other programs open on your desktop. To speed it up, close all the apps you don’t need. And don’t forget to quit all the background processes that demand power as well, such as Energy Savers, Spotlight Search, Time Machine, and FileVault.

Some more tips for streamlining your Mac’s efficiency include:

  • Setting a plain screensaver
  • Removing all icons from your desktop
  • Creating and logging into a new user account for iMovie

Optimize your Mac for iMovie automatically

While optimizing your Mac manually can seem daunting and repetitive, you can achieve even better results faster by using smart optimization software. A tool such as CleanMyMac X could be a perfect and quick solution.

Among other things, CleanMyMac X deals with storage, speed, and malware issues. It magically turns junk into free space. Here’s how to do it:

  1. Download CleanMyMac X (free trial available).
  2. Click Smart Scan in the menu bar on the left.
  3. Click Scan.
  4. Click Run.

The app makes it very easy to find those large cache files and “needy” programs that prevent your Mac from reaching its full potential.

Besides Smart Scan, it’s a good idea to go to the Optimization and Maintenance modules , where you can review other methods to give your Mac a much-needed boost.

Now your Mac and iMovie are ready for you to create your video masterpieces. You will want to repeat this cleaning process from time-to-time (at least once a month) to avoid any lags or disruptions, whether you do this manually or using a tool such as CleanMyMac X.

CleanMyMac X
CleanMyMac X

Your Mac. As good as new.