I started creating an app, and I was deleting a screen, and then all of a sudden it kicked me out of the app, and when I went to my projects to reopen it, it wouldn't open. I kept clicking it over and over hoping it would open, and it won't open at all! How do I reopen my app?
This URL allows you to open AI2 to the Project List, without opening any project.
http://ai2.appinventor.mit.edu/?autoload=false
From that list, you can request Exports of Projects without trying to open them.
Upload the troublesome .aia here.
You need to get into the aia file using a zip utility like 7zip and get into the project properties file with a text editor.
Change the last opened screen to Screen1.
This is a known bug