I was editing some quests and closing the quest book to check something in JEI when the world crashes and puts me back to the main menu.
2017-12-07-4.log.gz

Edit: After I removed an empty quest, closing the quest book now makes the whole game not respond.

There is nothing is this log file. Can you post another log file please? In its name there should be 'fml-client latest' or 'fml-server latest'

Do you mean "latest.log"?

Here is a picture, how it should look like: http://puu.sh/yB67F/456f6e682b.png
Here I would need the second file

Internet kind of slow right now. Can I do a pastebin?

Yeah do it

Actually, paste too big, pastebin won't allow. Please wait for me to upload file directly.

latest.log

The latest.log is also not enough. I could find an avidence that your problem is caused by HQM in both log files. You can try to delete the config folder of HQM, after backuping it and load the world

For backing up, should i just copy the world save folder onto desktop and delete the old one? Do I need to do anything else apart from that?

You just copy /config/hqm to any other folder and then delete the nonbackup /config/hqm

Ok let me try that and see if it fixes the problem.

No, it still crashes the game when I close the quest book.

Then it is another mod. What is the exact message you get when the world closes?

Then you have to do it the old way. Removing one mod, try the world. If it works than fine, otherwise remive the next one. I'll close this for now. If you find out that it is a bug with HQM than just reopen this issue

It just says internal server closed and puts me onto the multiplayer menu screen.