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.
Turns out it was just the specific asset I was trying to download....
I'm having this problem and installing monodevelop didn't solve it. Using ubuntu 16.04, unity-editor-5.1.0f3+2015090301_amd64.deb Any other...