Hmm, I may not have a Mac, but it sounds like similar problems that I have had. Though Idk how I fixed it, if you do end up having to reinstall though, you can simply take out all of the map files including the particles, terrains, map files, cfgs, etc. and put them on your desktop then when you redownload the game, simply move everything back. If it ends up still having that problem after all of this, then it may be something to do with the maps. Hope this helped! ^^Ill definitely give it a shot! Thought it will probably be a last resort, I thank you for your feedback!
Did you make sure you didn't have any double particles?I never really use particles when making maps, I like to think about the people who are going to use the maps. Though since this isn't the first time it has happened, I will definitely look out for files like that in the future. Thank you for your feedback!
Any files that you see that has a '_0' on the end of is usually the reason your game would be doing this, especially since map making is involved.
In the time span of 3 days, this computer has gone on and off repeatedly so it's definitely not a matter of restarting. Thank you for your feed back anyway!I use a mac and this happens often.
Restart your computer/laptop and re-open the game and it will open.