Answer by graslany

I have this error on Linux with the 2017.3 version. It's not necessarily related to a license issue (anymore). In my case, it's more likely a file permission issue. I installed Unity in /opt as root, then launched is a a normal user. Unity starts, but the console is spammed with lots of "package dependency failed to load" nonsense and my scripts do not compile (the compiler reports missing references to every single unity engine assembly). I copied the whole unity directory somewhere (cp -r /opt/Unity-xxx /home/myuser/somedirectory) as root then gave it to my normal user (chown -R myuser:myuser /home/myuser/somedirectory/Unity-xxx). Launching Unity from the copied, user-owned folder works as expected. This is obviously not a ideal solution since it forces you to copy the gigantic Unity folder once per user ; I played around a bit with the file permissions and another solution is to keep the original root-owned folder and make everything in it executable. The real, good solution would probably to make contact with the package maintainers at Unity and ask them to check which file exactly needs to have its permissions fixed, but I'm too lazy to do it right now :-)