Edit: After half day, my wife’s Mac started having the same problem. I have then applied the solution that I found in the Apple
Extract Sounds from Movies with Audio Hijack Pro
Let’s take a movie downloaded from YouTube as an example. To extract audio from it and add it to iTunes, you’ll need the following tools:
– VLC Media Player (freeware)
– Audio Hijack Pro (free trial)
Here’s a step-by-step guideline on extracting sounds from videos using this software.
1. Open the movie in VLC Media Player and pause or stop it.
2. Open Audio Hijack Pro.
3. On the left of its window, click Quick Record.
4. On the right of the window, select Application for the Input.
5. Choose VLC from the Select drop-down list.
6. Select the appropriate format for saving the record in the Recording part of the window.
7. Click Hijack and then Record to start the actual sound extraction process.
8. Use VLC Media Player to forward/rewind the video or pause it, if needed.
9. When the video is over, click Record again to stop the recording process.
10. The recorded audio file will be placed to the list in the Recording Bin.
11. Select the audio file and click iTunes in the Audio Hijack Pro Toolbar.
12. iTunes will open, automatically import the file and start its playback.