I have the latest version of the game, but didn't know I needed this mod to use blue-print stings. So now I have a great factory set-up, but cannot load any desired blue-prints. Is there a way to add and use this mod if you already have the necessary research completed?

The button should appear if you load a save with blueprints unlocked. Can you give me a copy of the save file that doesn't work?

Sorry Dave, I've been doing a lot of testing and that save is now gone. I had a combination of blue-print mods that may have contributed to the confusion.(Obviously) (Face-palm!) I have started a new map and will let you know if I have any further issues.

Long version:
I had started a game using a different blueprint mod(KSM?), and was having difficulty using it to import my blueprint string. So I added yours, and got an error message. I figured it had something to do with a conflict. So, I removed the old KSM? mod, and left yours there. I still got the error message...I assumed it was due to the fact that I had already researched "blueprints", but based on your response, I'm thinking it may have been the result of the previous blueprint mod somehow. Again, I'll let you know if I have any other issues.