When leaving a singleplayer world theres times where the game will be stuck at "saving the game" and it will not go past that.

Personally i have experienced this allot on alpha 3 and i have confirmation from the discussion place that it still happens in alpha 4

I would say (with a few other mods) it's 6s without c2me and 13 seconds with it. Update - it's more like 3 seconds for vanilla.
Probably not a bug or something that can be improved since the game with this mod is better threaded - "running multiple CPU cores in parallel" - and I think this is the cause of this issue.

for me it didnt just increase the waiting times a little i was gone for minutes and it was still stuck on that screen

gone for minutes and it was still stuck

I think I had this issue when I used C2ME with some other mod but I'm not sure now.

If you still can reproduce this deadlock with alpha 4 then upload your log so devs can check what's happening. Also, if you reproduced the issue then how many mods are you using? (Mod list)

ill take a look when i have time probably tomorrow

@leathium if you can, would you provide us some logs so it could help us to debug it faster.
Thank you

after testing i cant reproduce this on alpha 4 so i think it might be fixed

This is probably caused by c2me putting too much pressure on IO system. This won't be fixed in a short time but I will consider adding a progress bar.

Yup, had the same issue. It took so long I just Alt + F4'd out of the game

Does this also happen on dedicated servers?

This situation should be greatly improved by the new IO system: 43de197 2047c93 (enable it by ioSystem.replaceImpl in config, and make sure to get backups)

It still keeps the peace for a very long time, maybe jfr will help you:
c2me.zip

if your world's save is important try to wait 5 mins cuz it takes 2-3 mins to save my world (6 sec usually)

Closing as this is already resolved in #187