Hi there,
I've come across an issue after exporting an fbx from agisoft photoscan 1.21 into zbrush.
The zbrush project becomes corrupt and cannot be opened again when it contains an fbx with a TIFF texture.
I am able to save and reopen the same asset in zbrush if exported from an earlier version of agisoft photoscan or if I export from 1.21 as an obj. So this seems to be an fbx export issue in photoscan 1.21 specifically.