when i am trying to open my game file it does not open and show me error can't load. i want to know how to solve this problem and i am in desperate need because all my progress so far will be lost
Dropbox allows you to restore previous versions to a file that you have modified, has a change history of 30 days.
This is beta software. I save every few minutes and I store multiple copies of my bbdoc on both different hard drives and on Dropbox every hour..
That's good for not losing your file entirely, but it does not help you with versioning. You really need to have multiple versions saved to multiple locations or some kind of online versioning like Dropbox as recommended by jcalle.