iMovie error 10008

I am getting a video render error when trying to share my video. Renders about 25% (approx. 7 minutes) and then gives me an error. (iMovie error 10008: renderVideoFrame failed) as written in the notification.

I also noticed that the audio jumps from left to right and back again as I move the cursor up and down the timeline. The music will also disappear but come back when I click on the song next to it.

If anyone can help with this it would be greatly appreciated.

iMac High Sierra 10.13.2

iMovie 10.1.18

I am aware that the Mac OS is in need of an update.

Not sure about iMovie