unity fontainebleau importing error

Hey! I download the unity fontainebleau demo and opened with unity 2019.3.0 and the project was empty, all the assest was corrupted. I tryed with other 2019.3 version.. and the same resut... I tryed to open the images .. and it said that it is corrupted... also with the fbx file ... I have 999+ errors and this is one of the errors: Failed to load 'Assets/Graph/Models/Trees/SilverBirch_03_01_Prefab.prefab'. File may be corrupted or was serialized with a newer version of Unity.