A Unity ID allows you to buy and/or subscribe to Unity products and services, shop in the Asset Store and participate in the Unity community.
Separate names with a comma.
I don't really know what happened but it's working again now... Can't send you a bug report then ! Sorry.
I have the same issue on 5.3.3p2 version (and already with the 5.3.3f1 version). Application.persistentDataPath is returning an empty string in...