So I just spent a bit of time working on 1943. I hit save 3dn and exit. The next time I open the program and the rom, it won't load the 3dn. It says"An item with the same key has already been added." What am I doing wrong and is my work gone for good?

Which version are you currently using?

There is a bug causing it in v2.0.0 but it is already fixed in V2.0.1

Detail:

https://itch.io/t/204308/3dn-file-causes-hang-when-loaded

Please share here your 3dn url. I will fix it for you

http://s000.tinyupload.com/index.php?file_id=00044206339335471875

Here you go. Thank You.

The correct one for you:

https://www.dropbox.com/s/op9ry7r0tmzf7bf/1943%20-%20The%20Battle%20of%20Midway.3dn?dl=0

Sorry for the bad experience and late support.

The bug is already fixed so i believe it will never happen again!

Thank you and don't worry about it

I'm currently getting the same message with a .3dn file that I created for the game RoboWarrior. I'm using version 2.1.0, and it's happened twice now when starting from scratch. I tried starting from scratch and just changing a couple of things, but it seemed to load fine, so I'm guessing that something I've done both times is causing the issue. Here is the .3dn file:

https://www.dropbox.com/s/h32n724hw0kn518/Robo%20Warrior%20%28U%29.3dn?dl=0

Your fixed profile:

https://www.dropbox.com/s/8e5it2uyo0lm0w9/Robo%20Warrior.3dn?dl=0

The texture read from profile is null. I still don't the original reason yet.  Do you know steps to reproduce it?

Anyway  at least the profile will not be reset like that in the next version.    

Hey, thanks for that! I'll see if I can figure out a repro for it and get back to you; it may well have had something to do with the Merge function, which I used in both of the .3DNs that broke.