World is gone

This is already the second time this happens. The first time, I just created a new world with the same name and changed the last used computer ID, but it's a pain in the ass and I'd like to know what's causing it.

I didn't do anything wrong; I just quit my world and closed Minecraft, then when I opened it again, my world was gone.

Nothing you've said indicates computercraft is at fault. Even if you change the last I'd, that would not delete the world, or if it did, it is not replicable.

Your Forge logs might provide you with some clue.

Exception reading C:\Users\Usuario\AppData\Roaming\.minecraft\saves\ComputerCraft\level.dat
net.minecraft.util.ReportedException: Loading NBT data
at net.minecraft.nbt.NBTTagCompound.func_152449_a(NBTTagCompound.java:423) ~[dn.class:?]
at net.minecraft.nbt.NBTTagCompound.func_152446_a(NBTTagCompound.java:47) ~[dn.class:?]
at net.minecraft.nbt.NBTTagCompound.func_152449_a(NBTTagCompound.java:414) ~[dn.class:?]
at net.minecraft.nbt.NBTTagCompound.func_152446_a(NBTTagCompound.java:47) ~[dn.class:?]
at net.minecraft.nbt.NBTTagCompound.func_152449_a(NBTTagCompound.java:414) ~[dn.class:?]
at net.minecraft.nbt.NBTTagCompound.func_152446_a(NBTTagCompound.java:47) ~[dn.class:?]
at net.minecraft.nbt.NBTTagCompound.func_152449_a(NBTTagCompound.java:414) ~[dn.class:?]
at net.minecraft.nbt.NBTTagCompound.func_152446_a(NBTTagCompound.java:47) ~[dn.class:?]
at net.minecraft.nbt.CompressedStreamTools.func_152455_a(CompressedStreamTools.java:132) ~[dx.class:?]
at net.minecraft.nbt.CompressedStreamTools.func_152456_a(CompressedStreamTools.java:87) ~[dx.class:?]
at net.minecraft.nbt.CompressedStreamTools.func_74796_a(CompressedStreamTools.java:30) ~[dx.class:?]
at net.minecraft.world.storage.SaveFormatOld.func_75803_c(SourceFile:62) [atn.class:?]
at net.minecraft.world.chunk.storage.AnvilSaveConverter.func_75799_b(SourceFile:52) [atk.class:?]
at net.minecraft.client.gui.GuiSelectWorld.func_146627_h(GuiSelectWorld.java:83) [axv.class:?]
at net.minecraft.client.gui.GuiSelectWorld.func_73866_w_(GuiSelectWorld.java:54) [axv.class:?]
at net.minecraft.client.gui.GuiScreen.func_146280_a(GuiScreen.java:501) [axu.class:?]
at net.minecraft.client.Minecraft.func_147108_a(Minecraft.java:930) [ave.class:?]
at net.minecraft.client.gui.GuiMainMenu.func_146284_a(GuiMainMenu.java:257) [aya.class:?]
at net.minecraft.client.gui.GuiScreen.func_73864_a(GuiScreen.java:466) [axu.class:?]
at net.minecraft.client.gui.GuiMainMenu.func_73864_a(GuiMainMenu.java:555) [aya.class:?]
at net.minecraft.client.gui.GuiScreen.func_146274_d(GuiScreen.java:554) [axu.class:?]
at net.minecraft.client.gui.GuiScreen.func_146269_k(GuiScreen.java:523) [axu.class:?]
at net.minecraft.client.Minecraft.func_71407_l(Minecraft.java:1674) [ave.class:?]
at net.minecraft.client.Minecraft.func_71411_J(Minecraft.java:1024) [ave.class:?]
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:349) [ave.class:?]
at net.minecraft.client.main.Main.main(SourceFile:124) [Main.class:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_45]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_45]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_45]
at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_45]
at net.minecraft.launchwrapper.Launch.launch(Launch.java:135) [launchwrapper-1.12.jar:?]
at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.12.jar:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_45]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_45]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_45]
at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_45]
at info.mineshafter.GameStarter.main(GameStarter.java:24) [ms-starter.jar:?]
Caused by: java.io.EOFException: Unexpected end of ZLIB input stream
at java.util.zip.InflaterInputStream.fill(Unknown Source) ~[?:1.8.0_45]
at java.util.zip.InflaterInputStream.read(Unknown Source) ~[?:1.8.0_45]
at java.util.zip.GZIPInputStream.read(Unknown Source) ~[?:1.8.0_45]
at java.io.BufferedInputStream.read1(Unknown Source) ~[?:1.8.0_45]
at java.io.BufferedInputStream.read(Unknown Source) ~[?:1.8.0_45]
at java.io.DataInputStream.readFully(Unknown Source) ~[?:1.8.0_45]
at java.io.DataInputStream.readUTF(Unknown Source) ~[?:1.8.0_45]
at java.io.DataInputStream.readUTF(Unknown Source) ~[?:1.8.0_45]
at net.minecraft.nbt.NBTTagCompound.func_152448_b(NBTTagCompound.java:404) ~[dn.class:?]
at net.minecraft.nbt.NBTTagCompound.func_152446_a(NBTTagCompound.java:45) ~[dn.class:?]
at net.minecraft.nbt.NBTTagList.func_152446_a(SourceFile:66) ~[du.class:?]
at net.minecraft.nbt.NBTTagCompound.func_152449_a(NBTTagCompound.java:414) ~[dn.class:?]
… 36 more
[13:53:39] [Client thread/ERROR]: Exception reading C:\Users\Usuario\AppData\Roaming\.minecraft\saves\ComputerCraft\level.dat_old
net.minecraft.util.ReportedException: Loading NBT data
at net.minecraft.nbt.NBTTagCompound.func_152449_a(NBTTagCompound.java:423) ~[dn.class:?]
at net.minecraft.nbt.NBTTagCompound.func_152446_a(NBTTagCompound.java:47) ~[dn.class:?]
at net.minecraft.nbt.NBTTagCompound.func_152449_a(NBTTagCompound.java:414) ~[dn.class:?]
at net.minecraft.nbt.NBTTagCompound.func_152446_a(NBTTagCompound.java:47) ~[dn.class:?]
at net.minecraft.nbt.NBTTagCompound.func_152449_a(NBTTagCompound.java:414) ~[dn.class:?]
at net.minecraft.nbt.NBTTagCompound.func_152446_a(NBTTagCompound.java:47) ~[dn.class:?]
at net.minecraft.nbt.NBTTagCompound.func_152449_a(NBTTagCompound.java:414) ~[dn.class:?]
at net.minecraft.nbt.NBTTagCompound.func_152446_a(NBTTagCompound.java:47) ~[dn.class:?]
at net.minecraft.nbt.CompressedStreamTools.func_152455_a(CompressedStreamTools.java:132) ~[dx.class:?]
at net.minecraft.nbt.CompressedStreamTools.func_152456_a(CompressedStreamTools.java:87) ~[dx.class:?]
at net.minecraft.nbt.CompressedStreamTools.func_74796_a(CompressedStreamTools.java:30) ~[dx.class:?]
at net.minecraft.world.storage.SaveFormatOld.func_75803_c(SourceFile:73) [atn.class:?]
at net.minecraft.world.chunk.storage.AnvilSaveConverter.func_75799_b(SourceFile:52) [atk.class:?]
at net.minecraft.client.gui.GuiSelectWorld.func_146627_h(GuiSelectWorld.java:83) [axv.class:?]
at net.minecraft.client.gui.GuiSelectWorld.func_73866_w_(GuiSelectWorld.java:54) [axv.class:?]
at net.minecraft.client.gui.GuiScreen.func_146280_a(GuiScreen.java:501) [axu.class:?]
at net.minecraft.client.Minecraft.func_147108_a(Minecraft.java:930) [ave.class:?]
at net.minecraft.client.gui.GuiMainMenu.func_146284_a(GuiMainMenu.java:257) [aya.class:?]
at net.minecraft.client.gui.GuiScreen.func_73864_a(GuiScreen.java:466) [axu.class:?]
at net.minecraft.client.gui.GuiMainMenu.func_73864_a(GuiMainMenu.java:555) [aya.class:?]
at net.minecraft.client.gui.GuiScreen.func_146274_d(GuiScreen.java:554) [axu.class:?]
at net.minecraft.client.gui.GuiScreen.func_146269_k(GuiScreen.java:523) [axu.class:?]
at net.minecraft.client.Minecraft.func_71407_l(Minecraft.java:1674) [ave.class:?]
at net.minecraft.client.Minecraft.func_71411_J(Minecraft.java:1024) [ave.class:?]
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:349) [ave.class:?]
at net.minecraft.client.main.Main.main(SourceFile:124) [Main.class:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_45]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_45]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_45]
at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_45]
at net.minecraft.launchwrapper.Launch.launch(Launch.java:135) [launchwrapper-1.12.jar:?]
at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.12.jar:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_45]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_45]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_45]
at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_45]
at info.mineshafter.GameStarter.main(GameStarter.java:24) [ms-starter.jar:?]
Caused by: java.io.EOFException: Unexpected end of ZLIB input stream
at java.util.zip.InflaterInputStream.fill(Unknown Source) ~[?:1.8.0_45]
at java.util.zip.InflaterInputStream.read(Unknown Source) ~[?:1.8.0_45]
at java.util.zip.GZIPInputStream.read(Unknown Source) ~[?:1.8.0_45]
at java.io.BufferedInputStream.read1(Unknown Source) ~[?:1.8.0_45]
at java.io.BufferedInputStream.read(Unknown Source) ~[?:1.8.0_45]
at java.io.DataInputStream.readFully(Unknown Source) ~[?:1.8.0_45]
at java.io.DataInputStream.readUTF(Unknown Source) ~[?:1.8.0_45]
at java.io.DataInputStream.readUTF(Unknown Source) ~[?:1.8.0_45]
at net.minecraft.nbt.NBTTagCompound.func_152448_b(NBTTagCompound.java:404) ~[dn.class:?]
at net.minecraft.nbt.NBTTagCompound.func_152446_a(NBTTagCompound.java:45) ~[dn.class:?]
at net.minecraft.nbt.NBTTagList.func_152446_a(SourceFile:66) ~[du.class:?]
at net.minecraft.nbt.NBTTagCompound.func_152449_a(NBTTagCompound.java:414) ~[dn.class:?]
… 36 more
[13:54:51] [Server thread/INFO]: Starting integrated minecraft server version 1.8.9

What does that mean?

That looks like a corrupted save, and (aside from the world name) there's no mention of CC anywhere.

Then why is my CC word the only one this ever happened?

I know It's a corrupted save, but I want to know why.

Note, it happened twice.

The logs from when the world was last working would be rather more likely to shed light on how it went to a "not working" state, than logs from after the fact.

There's nothing abnormal from before that. Just "can't keep up" and loading/unloading dimensions.

Well, I think so, will look at it later