iMovie project no sound after update to iMovie 10.1.8

So you lost audio in your iMovie project after update to version 10.1.8? Actually, this is a common issue on iMovie 10.1.8 with macOS High Sierra. To solve the issue, we would recommend transcoding your project to AIC .mov previously before editing.
 iMovie 10.1.8 erased audio in my project

iMovie 10.1.8 erased audio in my project, how to fix?
“Hi all, I recently updated to macOS High Sierra and iMovie 10.1.8. There is something wrong when I opening one of my latest projects in iMovie 10.1.8. The audio in the project is playing too slow and large chunks of the audio clip were erased. The entire clip still exists in the green bar, only big sections of it show no waveform and the audio is gone. What should I do to fix the issue? Please advice. Thanks.”

You have two options to solve the issue:
1. Replace the audio with the originals
2. If you don’t have backups of your original audio files, or they are messed up, converting your project to AIC using a third party converter would be a good idea. We explain how below:

How to convert iMovie project to Apple InterMediate Codec?

Here’s what you need
HD Video Converter for Mac
iMovie project no sound after update to iMovie 10.1.8

To transcode iMovie project to AIC for iMovie editing, do as below:
Step 1: Click “Add File” to load iMovie project files into this program.
iMovie project no sound after update to iMovie 10.1.8

Step 2: Click “Profile” to select “iMovie and Final Cut Express” > “Apple InterMediate Codec(AIC) (*.mov)” as output format. AIC .mov is iMovie’s favorite editing codec, which iMovie will recognize and handle well.
iMovie project no sound after update to iMovie 10.1.8

Step 3: Custom video and audio settings
If necessary, you can click “Settings” button to modify video and audio parameters like encoder, resolution, frame rate, bitrate, aspect ratio, sample rate, and audio channels. You can also “enable 3D Settings” to add 3D effect to your source media.

Step 4: Click “Convert” to start iMovie project to AIC conversion on High Sierra.
As soon as the conversion is complete, click “Open Folder” to get the generated AIC .mov files for editing in iMovie with optimum performance. Hope it helps.

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