As duplicate particles tend to be the #1 culprit for issues like this, I encourage you to double check by typing "Particle" into your file search bar after accessing the FH folder. Delete anything ending with _0, _1, _2, _3, etc.
Also, if you downloaded or made your own custom terrain texture, for example a grass texture or a sand texture, if it isn't 512x512 and in RGB mode, it will crash your game.
It's also come to be that for some users, the .obj files don't export with the rest of the map. If that's the case, you and your friends won't see the objects from those specific .obj folders that didn't export. You'll have to go into the Objects folder and pluck out the .obj files used in your map and place them manually into exports.
You'll have to place them in a zip folder and put them up as a separate download for your friends if that is indeed the case that they were never exported in the first place.
Side Note: When you import meshes from other people and have to manually enter the object in "Object Maker", make sure you save it to its own group. If you save it to, for example, My Trees or My Rocks, it will cause your game to crash.Never ever ever mess with those object groups, don't delete meshes from them, don't add meshes to them.
Also, if you downloaded or made your own custom terrain texture, for example a grass texture or a sand texture, if it isn't 512x512 and in RGB mode, it will crash your game.
A terrain texture only has to be in RGB mode and .jpg (or it could be .png I can't remember which), but the size of it doesn't really matter or at least it didn't used to, I've used terrain textures before that were 1040x1040. They work just the same.
Not only this, but when I create objects in the map maker and I try to put them in my map, once I export it they cannot be seen. This includes importing meshes from other people. If the people have an object file to group their objects already they work; but if I have to load the mesh and save it myself, it won't work. For example, I tried loading in an individual log mesh. It worked, I put it in my map and it was perfect. But, once I export the map, it's gone. Another example, I wanted to make a group of reeds so I didn't have to place every reed individually and I had the same problem.
Did you EXPORT your objects? Or did you just SAVE them? Exporting your objects can make a whole lot of difference. If you only save them in Object Maker, you'll only be able to see them in Map Maker but not in-game. If you export them like you should, you and whoever you share the map with will be able to see the objects in-game. Simple. When you download objects from other people that are already in their own groups, they (or at least they should of) have already exported the objects into the groups they're contained in, which is why when your map is exported you can see just those objects in-game but not your own. Objects you download that don't have their own groups are objects you must export from Object Maker yourself into your own object group before you use it in a map.
Hopefully someone takes notice, This is a serious issue and needs to be handled before it gets out of hand. It would be nice for having the freedom of making our own maps for private groups/friends. I am hoping Raz takes notice of this issue, A patch may be needed to fix it. I encourage any Staff who read this to test it out for yourselves, It does happen and it is very annoying. Not only does it corrupt the 'Export' Files but it corrupts the whole game, You are going to have to re-install the game each time you attempt to export a map.
Thank you for putting this into better words for me, I was rather peeved off at the time and wished to have a solution asap. Hopefully this gets sorted as soon as possible.
OK so obvously it isn't a particles issue as is constantly suggested in this topic. Now that I think back I was having problems trying to get my podium map mod to export a while ago, although it wasn't like your issue it was still a nuisance, my Map Maker just simply failed to export. However it seemed changing rendering systems helped so again I suggest giving that a try if you haven't already.
If that doesn't work, it could be that you have a faulty object somewhere or the map's .cfg files are corrupt, SO my solution to that would be to take a look at this tutorial here---> https://m.youtube.com/watch?v=RfTBPlFQYUs
You can use that tutorial to create a new copy of your map and still have all the objects in place like before by following the steps in the video to copy/paste the coding from the .cfg files. Once that is done, give the exporting a go and see if there are any changes AT ALL and let us know the results.
I'm sorry I couldn't help more, I'm stuck using mobile devices and don't have access to my game's files to have a further look at things, and probably won't for a little while longer.