I believe the issue is that you are cancelling out of the RenderAs dialog which will result in the state of the dialog not saving. If you choose favorites and proceed to render out the clip, I believe the favorites will then be saved.
It's worked that way for a loooong, loooong time. I don't have Vegas 4 or 8 still on a machine but 9.0e required that you, at least, start a render to save the state of the dialog box.
Hi @Former user, one question since you use earlier versions and render settings.
I have save some personnal templates for render, since moviestudio platinium 10, they were auto imported on vegas movie studio platinum 13 without doing anything
but not in vegas movie studio 16, did you happen to encounter the same thing ? and if yes did you solved or you just recreate them.
@DJCarlos My experience is that up to and including VMS Plat 15 the Render Templates folder was at Users\UserName\AppData\Roaming\Sony\. With VMS 16 it switched to Users\UserName\AppData\Roaming\Vegas\. VMS16 found my templates in the old Sony folder but put new ones in the Vegas folder. It obviously searched both. I've now copied them all into the Vegas folder. If you do likewise it might solve your problem.
PS. This is the Pro forum and Veg was talking about Vegas Pro 16. I believe Vegas Pro stores templates somewhere different to VMS.