I am making a Minecraft map,and I seem to have lost one of the unfinished builds in the map. I've looked everywhere I can but I can't find it. Is there a way to track down the coordinates of the build? I did use structure blocks if that's any help. I can track it down myself but I need to know a way to do so. Other useful info could be that I use Windows not Mac, and I am running Minecraft 1.12.Thank you for the help.
there are ways...
safest way (not that there is anything unsafe about mods, if you know where to get them from) is to use mapping software - external programs which will read your save data and generate a huge png image showing areas you have explored. once you have the map you should be able to recognize any structures (assuming they are large enough and on the surface).
mcedit isn't safe because it's complicated and original poster doesn't sound very savvy. let's skip that one. it's a great thing but it can destroy worlds.
nbt-editors (even better - nbt viewers) can be used to get coordinates of explored chunks; if the original poster writes down most remote explored chunks and teleports into them, he might recognize (or bump into) his fort/lighthouse/whatever (just write down first; world save file will change).