Preview won't work, even after Restarting the program

I just made a project and the preview won’t run, it just gets stuck at 100%. the odd thing is that I have an older game and the preview works there. I haven’t put any effects (I don’t even know how) so I don’t how it’s flubbed up. the version I have is the newest one. can I get some help?

edit: turns out something happened with the saving and it deleted itself (maybe). IDK how this happened

Use debugger to check what’s going on.

Often, it’s because of a ‘while’ loop that gets stuck, or an asset (image, sound) that is missing.