When you have unwanted keys on Meshsmooth/Turbosmooth modifiers, it can be a pain even if the iteration value does NOT actually change. If you have hair and use Vray moblur/displacement, it may crash if you have these keys in your scene.
These keys are created when you hit the big Set Keys button and your Key Filters has Modifiers checked. Use this script to get rid of these keys (and optionally material keys as well).
As usual, back up your file before running the script. Just drag and drop the script into your Max viewport to run.