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.
Deactivate Antivirus(and Firewall if if does not work). And voila!
Same problem! Windows 7 Ultimate, 64-bit Intel Core i7-4500U, AMD Radeon R9 M270X , 8GB RAM