Help! My whole world disappeared

Me and 3 of my friends play on SMP server. I was playing today, and when i finished i shut down the server. My friend came 30mins later, and when he started the server and tried to log in, it said that he isnt whitelisted(we have whitelist on our server). He added himself on whitelist, but when he entered the world, it spawned him in totally new world.

Our world is gone, and every played from whitelist is gone, but server ip and server settings stayed the same. I have no idea how this happened and why, but we invested a lot in this world and it would be a shame if we lost it to some kind of bug or whatever it is.

Can somebody help me, since i have no idea what i can do.

Quote from Stally3

that does happen sometimes, maybe reupload it and see if It works

Reupload what? My world is gone. I have backup file from few weeks but file is too big so aternos cant accept it, and even if it could, we would still miss a lot of what he did in those few weeks

Quote from Mc88Donalds|Julian

If your world is too big to upload it you can use thanos (https://github.com/aternosorg/thanos) to remove unused chunks. i made a short tutorial on how to use it (

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)

thanks, that will be my plan B. But i would still like to know why my world disappeared without a reason and if i can get it back.