So Core keeps using a ton of storage whenever I open it. I opened it to develop my game yesterday and it used up 5 GB, did it again today and it used another 5 GB. Closed and opened it to see what will happen and it used up 200 MB, restarted my computer to see if it'll free up some storage but now there's another 200 MB taken up. Can someone please help me with this? Is this normal??? Is Core really that storage inefficient??
I don't know if you are talking about memory or storage since you are using both terms, my message will talk about memory specifically. But it usually depends on how complicated your game is. If you have a ton of objects, scripts, and folders, it is usually stored to memory to provide a better experience for the user. Core will store data to RAM or memory because it is fast and quick to read when needed, versus when you save it to storage where it will take longer to retrieve and run again. Memory is short term and it will stay there until you close the window or turn off your computer. Although 5 GB of memory does seem excessive. The 200 MB is probably to help the menus load faster. Hope this helps you understand! 
Sorry for the confusion, I'm a software developer so I didn't mean to use them interchangeably but just happened to write memory instead of storage. And Core has still got the issue of taking up huge chunks of storage. I'd appreciate it if you could help. Oh! And it freezes up every time it autosaves which is frustrating
The current install of Core takes 6 GB (this is typically C:\ProgramData\Manticore Games) in addition to this you will have a storage requirement for any games you are developing (this is typically in C:\Users\you\Documents\My Games\CORE) and will entirely depend on how much development work you have done - after messing around for about a year I have 2 GB here.
When you say you closed and opened Core and used 200MB, that does not make much sense (given the install size is 5GB+) Perhaps you were looking at your development area? Although you should not see any change in size from just opening it. When I start Core and open a project I do not see any change in my disk space usage.
Sounds like you need to do some investigating and find out exactly where your storage space is being used and what the file name is.
Maybe Core has buffer room? Core may take up a certain amount of storage assuming that you will fill up some of it, but then once you close the app it gets rid of that buffer, allowing other applications to use it. It may do this if you don't have enough RAM to temporarily store the game files, but enough to run the game... I have no idea to be honest, just a theory. (Wikipedia Article) As for the game freezing, it may be because the rate the game can save to the drive is too slow for the game. Just try searching up "Write speed of " on google. If you need help getting your drive you can open task manager by hitting ctrl + shift + esc and going to the performance tab, then disk, then in the top right it should show the drive name. You can also just look at task manager to see what is using the storage space, like RedQuad said. Edit: Also, if you have any other applications open like chrome then close it or close some tabs. Chrome takes up a lot of memory.
Good points, I'm not running out of RAM so maybe that is why I don't see any disk usage change when I open Core.
I've got an SSD and a 16 GB RAM so I don't think the problem lies on my end, besides I've checked all my game folders, the manticore folder plus the temp folders, and it doesn't look like they've gone up any significant amount even though it seems Core is still piling up storage. I've also recently noticed that it starts to take up a lot more each time I expand my game, now I've only got 35 GB left of my 512 SSD....
Hmm. Do you have any excessive prints, like something that prints every tick or frame? It may store to a log which may take up storage. If not you will probably have to ask a Manticore employee, or email support. There should also be runtime logs for the application, I have no idea if it has save-to-storage logs. Maybe look at those if you can. Sorry I couldn't help more.
Nope, looks like I'll have to email support. Do you know their email cause I couldn't find it?
You can join the Discord and someone else may be able to give you an answer. (https://discord.com/invite/core-creators) Or you can file a report here: https://support.coregames.com/hc/en-us/requests/new.
Thanks