iMovie Freezes and Video Export Failures

The problems that you describe can be caused by a number of things. Does the "Export Fails" message contain any more information? If so, please post its exact wording.

Try working your way through these troubleshooting procedures to see if you can isolate the problem:

Deleting Preferences

Open iMovie while holding down the Option and Command keys and select to delete

preferences in the box that appears. iMovie will open in a new library. Reopen

your old library to get back to your projects.  Deleting preferences is a safe procedure that

will not cause data loss or disruption to your project.

Opening iMovie in a new library

Try opening iMovie in a new library.  To do

that, open iMovie while holding down the Option key and then selecting to

create a new library in the box that appears.

Opening iMovie in a new user account

Create a new user account from System Preferences/Users and Groups and try to open and

use iMovie in the new account. You can use the Guest account on your Mac for

this purpose.

New Project

Another thing you can try is to copy your media into a newly created project and see if

that cures the problem. To do that, do an Edit/Select All, Edit/Copy, of the

media in your project and then Edit/Paste it into the newly created project.

Safe Mode

You could also try booting up in Safe Mode (see Finder menu for instructions) and,

after everything loads, immediately shut down and reboot in normal mode. Then

see if iMovie works properly.

Updating iMovie

To update/redownload iMovie 10, drag your iMovie 10 app from the Applications

folder into the trash, but do not empty the trash. Sign in to the app

store and open your purchases folder by clicking on your name at the bottom of

the app store side bar. You will see your purchases displayed, including iMovie 10. Redownload/update

iMovie from there. If not successful, drag your present iMovie app out of the

trash and return it to the Applications folder.

Resetting the System Management Controller

Try resetting the System Management Controller (but no longer available for the new

M1 computers):

https://support.apple.com/en-us/HT201295

Resetting the NVRAM

or PRAM

Try resetting the NVRAM or PRAM, although this issue would be fairly rare:

https://support.apple.com/en-us/HT204063

Contact Apple Support

If none of the above resolve your issue, contact Apple Support.  The techs there have the capability of

remotely accessing your computer that we cannot do here.  To contact apple support click on the Contact

Support item in the upper right hand corner of this forum’s screen.  Navigate to a place where you can enter your

phone number.

-- Rich

The only other thing that I can think of is that possibly you have insufficient free space on your computer to allow iMovie to function efficiently. iMovie should have at least 10 GB for a safe margin. Go to Apple Logo/About this Mac/Storage and see how much free space that you have. If you don't have enough you will need to move or delete some files from your Mac.

Otherwise, as I mentioned in my previous post, I recommend contacting Apple Support to talk with the techs there, who have the capability to remotely access your computer.

-- Rich

Yeah, the support techs may be able to get to the bottom of it. Tell them all of the diagnostic procedures that you have tried.

Good luck with this.

— Rich