I can't reproduce your error. I downloaded the zip, created two new projects and a copy project and everything went well. I open them without error.
Could you tell me a little more so I can reproduce the bug.
How did you update with a fresh install? I would like to follow the same steps as you to try to reproduce the bug, because it seems to work well for me.
At worst, empty the _Project/ directory and try to create projects again (by not clicking on the create button several times, there is a small waiting time when you create a project before the project manager starts). poster.