Can not save HDRP render or post processing settings in 2019.1

Same here! ... 2019.2.01 I've tried a number of times and render settings and post processing all lost every time!

I've tried save scene, and save project How can we work on a project when we cant save it?

Might be the Volume you're using is the default and getting package-managed-overwritten?

Try creating a new Volume in your assets folder (right click project>create>volume profile), attach it to an empty game object in the scene and make sure 'Is Global' is checked. You also probably want to do the same for your own HDRPAsset (create>rendering>HDRPAsset), w$$anonymous$$ch needs assigning at the top of edit>project settings>grap$$anonymous$$cs.