By reimport I mean deleting the character I have and importing a new one.
OK, had a feeling that's why I called it a stupid question.
The sync button is specifically for your use case: you have something you've continued to work on and want to include a change from MH in that work without losing what you've added.
That's what I thought. My change in MH was changing the pose from a standing pose to sitting.
But as you've seen it is not always very stable.
In other words do what I did which was to save what I had prior to mashing the sync button. Got it.
Peter L. Berghold <peter@berghold.net> or <Salty.Cowdawg@gmail.com>
Retired IT with 30+ years in the business