I updated to unity 2018 but cannot load my project how can I get around this?
the latest bata of 2018 to the official release
I ran into this exact same issue. I was running a higher version of a package (I think ShaderGraph) than what was allowed in the official release.
Easiest solution: Reinstall the original version, open up your package manager, and downgrade the packages to the official releases, and then reinstall your new version.
From this topic, looks like running Unity as administrator solves the problem.
Also, if that doesn’t work, from this answer, a Unity official provided the steps: