The prior tips for freezing a track containing a sidechain device assume that you’re fine with the device being at the very end of the effect chain. For example, what if you’ve got a sidechained Compressor sitting before EQ and distortion? If you move the compressor out of the track, then add it back after freezing, you’ll end up with the compressor at the end of the chain, resulting in a different sound than you started with.
In some situations, you’ll follow the same procedure, but instead of parking just the compressor on another track, you’ll have to move the compressor and every device that follows it. I usually rack them up first, since it makes them easier to move around as a group.
Then, after the track is frozen & flattened or (frozen and grouped), you return the entire rack into the signal path.
But wait! Doesn’t this defeat the purpose of freezing somewhat? Yes, often times it does. For example, a UAD Neve 1081 uses up almost half of my laptop UAD card. I need to freeze the track to get some processing power back.
In that case, you’re stuck with good old fashioned rendering. Use Export Audio/Video to render an audio file of the track in question…
…then import it back into the set.
(You can also use record directly into a new track to capture the audio, but I usually export cuz it’s faster.)