Recently I had to upgrade from Unity 5.6 to Unity 2017 and the transition was not smooth. After hours of struggle I was able to do it.
Here's what I learned:
- Installing Unity 2017 and upgrading the project is not enough. If you do that and have some dependencies, when you try to build you might get a crash (access violation ...)
- You need to recreate the project using an empty project
- Next, before dragging all assets to the new project, you need to import all packages used (for example google play services, google ads, in-app purchases, photon unity network... etc).
- Configure all the packages that were installed
- Drag all project assets from the old project to the new project
- Compile and voilá, done.
Note: you cannot install packages if you have errors, thats why it is important to install the packages first, to avoid dependency errors from your scripts. If you don't do it, the packages configs won't even show up in the menus.
Ok, thats it, I hope this helps someone.