level.dat is being used while loading singleplayer world

[minh0509]

Title:

level.dat is being used while loading singleplayer world​

Launcher Version:

1.4.8​

Modpack:

FTB Departed​

Modpack Version:

1.2.1​

Log Link:

​

Details of the issue:

I was playing earlier, suddenly my computer got shutted down by a power cut. After that, I relaunch the computer and the game. and when I load my singleplayer world, there is a message:
"Forge Mod Loader detected that the backup level.dat is being used. This may happen due to a bug or corruption, continuing can damage your world beyond repair or lose data/progress. It's recommended to create a world backup before continuing."
And it has 2 buttons: Yes or No. If clicking yes, nothing happens. If clicking no, it takes me back to the title screen.
I've tried to create a backup but it wasn't work. What should I do now?
(Sorry for my bad english)​

 

[King_Dennis]

Try using this guide to backup your world, instead of vanilla do it for FTB obviously. Any questions feel free to as me. Best of luck!

 

[NanoPlex]

Hey, I have the same problem with my world and tried the guide. It has also worked so far that the error message is gone, but now the game crashes when loading the world. I have also tried many other methods, but none works.
If anyone has any ideas, I would be very happy about help.