Audio speeds up - checked FAQ answers. Please help!

Heya! So I’m a total newbie to this, been teaching myself how to use Audacity and it’s been fine thus far. I’ve started making 1hr videos for a project and for some odd reason the audio keeps speeding up and unsyncing from the video. My hardware is a brand spanking new Macbook Pro and a Blue Yeti mic.

So I record the video using PhotoBooth (which also records audio which is synced) and I record the audio through Audacity. All I do is a noise reduction and a normalise to make it sound a bit better but when I chuck it in with the video in iMovie the Audacity audio is shorter than the audio recorded through Photobooth.

These are the things I’ve done to check:

  1. Tried exporting the audio without editing it - it’s still short.
  2. Exported the video from iMovie into GarageBand, saving it as an audio file, putting that into audacity and then editing and putting it in - still somehow speeds up the audio.
  3. Checked the sample rate / formatting stuff (literally don’t know what that is but it’s the same on my Mac and Audacity).
  4. Tried exporting the audio file from Audacity as a WAV and MP4 - didn’t make a difference.
  5. Checked the “speed up/slow down” effects - they’re at 0.

The strangest thing is that the first 15 minutes is fine for the most part, but the longer the file goes the more discrepancies I noticed. I had to patch in audio from the Photobooth in quiet moments to then resync the Audacity audio. Towards the end of the video it was starting to get noticeably desynced after a minute. I can share some pics but I dunno what would help.

If anyone has any ideas I’d really appreciate it! I’m a lil busy today but I’ll certainly check this after 7 and try anything anyone suggests. Thank you all!

PS. Audacity is really awesome! I’ve been having a jolly good time with it - just this is confusing!

How much shorter is it? Please give an example of the track durations and the amount of difference.
Is there any noticeable difference in pitch (as well as the difference in duration)?