Did you use some third party plugins? If you have done an update, your third party plugins still remains at the previous After Effects installation folder. You need to reinstall or move them to the new plug-ins folder for CC2018. This could be the problem
If you are not using third party plug-ins, you can delete your preferences. As soon as you launch AE, hold Control/Comand+Alt+Shift. You will be prompted to delete your preferences. AE will generate a new set of preferences. Then, try to open your project and tell us if it works.