u/AssociateFluffy8580

So I was new to GNS3 due to it required in my semester class, but is there's a settings I need to do in order to be able to open my previous project? For example, I have this project I have work on for a day (project is connected to VirtualBox, I wonder if this, too, could affect how project are saved), and then I close said project only to unable to open it the next time I open them. The option open project and opening it from recent project resulted in same thing. And this problem occurred too to my friends and we haven't yet found a solution for said problem.

Is there any tips on how to 'save' project properly or to prevent this from happening?

TIA