Steps to reproduce:
Software version (for both creating and trying to open the saved file): 2.4.2
Platform: Mac OS X 10.11 El Capitan
@GitGianluc - Can you open the .osp file in a text editor and check if it actually has content? We came across this before but basically the file didn't save due to a sudden system shutdown. Different case to yours of course but maybe the file is also blank for you.
@DylanC – That's a good point, thank you! Anyway: I opened the file in Sublime Text and it's not empty... :-(
@GitGianluc - I will give this a try on my Mac for you.
@GitGianluc - I think this is directly related to #2162. He can open project files from inside the editor but not via the file manager.
@ferdnyc - Did Openshot open project files if passed via an argument to the main binary? I would find it strange if it never did this.
That's an excellent question. It _must've_, since the .desktop file includes the line:
Exec=openshot-qt %F
Which means this is something I broke when I added the command-line arguments. I'll look over those changes and get it fixed up ASAP.