Here's a mediafire version of the map. I hope it helps.
http://www.mediafire.com/file/llnggas685x38ka/The_Syndicate_Epic_Seed_%21_-_Copy.zip
I've done everything you've suggested, and I still can't open the world. I've updated Java, I downloaded the better launcher, I updated my entire OS, and yet it still won't open. I'm uploading it to mediafire, I will put a link here when it is uploaded.
I'll see what I can do. I updated my Java and my computer as a whole, and the issue is still there. I just want this world back. If it means undoing the structures, that's fine.
I can't. It's over 600 mb and the limit here is 10
Will this update fix my world or is it permanently corrupted?
Thank you so much! This did the trick, and now I have my world back. I think I know how I caused the crash. The structures I used were all part of the same ship, and I accidentally made it so that they overlapped on a single layer. This meant that when I used the two structures, they ended up both putting blocks in the exact same place.
Again, thanks for the help. I never would've figured this out on my own, and thanks to you, I have my most important world back. I promise to be more careful with structure blocks in the future.