Trouble Opening OpenRocket files

I've just started playing with Open Rocket as I am going to start my first scratch build soon. I made a test rocket to play around with for learning purposes and saved the file to my desktop. When I go back to that file to Open it I get an error message saying that "Windows Can't Open This File:' That was on my work computer. I saved the file to a thumb drive and tried it on my Mac and had the same problem. Both computers have the free OpenRocket software download on them, version 13.11.2. When I go into the Open Rocket software where I created the file, I can access my test rocket file through the 'File - Open Recent' dropdown. I searched the first few pages under the "Rocketry Electronics and Software' threads on this forum, but couldn't find a solution. While doing that I came across a few threads with .ork files attached. The same thing happens when I try to open those files..... Help!

You're probably trying to click on the .ork files to open them? While there's probably some Windowsy way of doing file association, most people just start Open Rocket, then open the file afterwards.

Yes, you are right. That was my first error with openrocket. You have to open the files through openrocket.

Because OpenRocket is not a traditional .exe program, windows will choke, and not be able to figure out what to do. Launch OpenRocket first, then browse to the file you want to open, and it will work.

That was it! Not launching OpenRocket and opening the saved file through the program was the error I was making. Got it working on both my Windows laptop and Mac. Thanks!

Another helpful tip is to navigate to Edit->Preferences->Options and make sure that the option "Open last design file on startup" is checked. That eliminates having to navigate to your design file once Open Rocket has started (assuming you want to edit the last design you worked on). There's also File->Open Recent that is a quick list of the last 9 design files you've edited.

Cheers,
Doug