A chunk with previously generated data was cleared, all the blocks and data within vanish

The developer of a popular world and chunk corruption fixer software told me that in recent versions of Minecraft, corrupted chunks re-generate themselves.

All of these problems are ´cause the world is default Multiplayer, the world will not save properly.

I experienced this reset yesterday after a series of previous crashes.

Minecraft 1.4.7
Microsoft Windows 7 (64bit)
Java 1.7.0_04

Initially Minecraft would crash whenever I dug sand blocks (id: 12). Mid destruction, the game would freeze. I'd close the game, restart and gameplay would be normal again. Suddenly as I open a large chest in my log cabin, on a plateaued mountain, the game freezes once more. Only this time, when I restarted the game the chuck I was standing in reset. I lost two large chest of all my food and valuables (emeralds, diamonds, redstone, lapis lazuli, etc...)

I also experienced this problem. We told me it was because I placed a jukebox but when I restored this chunk (I had a backup) I noticed the jukebox was on the neighboring chunk which remain untouched. Weird!

Confirmed - More in 1.5 but i decided a term for this which is DE-GENERATING it is where the chunks light will go its gravity almsot go so you fall excedingly slowly and all blocks or similar things removed...It is unknown why this happens but it can happen in 1.5 up to 20 chunks suddenly degenerate you also get PAR-DEGENRATION where only liquids degenerate yet odly you can still fall...Although the claim of it REMOVING USER PLACES BLOCKS is unknown to me...it does cause terrible lag and is common when using fast movement
Belief of cause:Minecraft being to slow or being to full or to unstable therefore in a self presevation attempt almost it removes some chunks but in the problem of it being slow or unstable it will degenerate wrong chunks and POSSIBLY remove user placed things only to re-apeer as normal at start of world thanks to the seed being remebered via minecraft...a reason why making 2 worlds same seed the second 1 will generate quicker becuase of seed memory a complex thing but thats abit off topic I couldnt point out a individual bit of coding for this although i realised something which then i used to INDUCE the chances of this possible bug happening which is on multiplayer using a plugin such as Multiverse the worlds would almost 'Trade chunks' where you might have a nice flatlands and suddenly it has a chunk of a skylands world maybe flatland not all being flatland is a bug itself thats why i did it with planetoids, skylands, Large biomes, Desert only world and another type of flatlands...that was a old experiement and i have lost the images due to a crash but this should be kept in mind...YOU DO NOT NEED TO EXIT CHUNK TO INDUCE THIS BUG OR HAVE THIS BUG HAPPEN IT IS TECHNICALLY NOT A CRASH BUT A BUG BECUASE OF THE LAG INSTABLE CONNECTION OR LACK OF SPARE SPACE CUASING EXIT OF GAME!

Vladimir yours may be a SPECIAL variation of bug the or possibly a different bug all togher i advise to post that bug seperately becuase its whole chunks degenerating instead of blocks 'WANDERING' as i would be forced to put it

Why is This Bug not fixed yet?
It is a vary big Game Breaker.

OK I Have typed the same massage twice now, both times they have mysteriously disappeared. I would Never say anything offensive on the web, so its not that. I'm not blind I know I typed in and clicked add so its not a mistake on my end.
so what happened? I'm already getting this from my game I DON'T need it on a forum.
So here is the message AGAIN:WHY has this darn BUG not been FIXED its been MOUTHS sense it was reported.

Because they have no idea what causes it. If they can't reproduce it internally, how are they supposed to fix it? They'll discover the problem on accident, or maybe in a thorough review of the entire codebase. It's not enough for people to just yell "THIS BAD THING HAPPENED TO ME MAKE IT NEVER HAPPEN AGAIN". If problems were that easy to solve, we wouldn't have war and starvation.

Most people never experience this. It might not even be a bug within Minecraft itself, but in the user's system, whether it be their OS, their user permissions, Java, or one of the libraries Minecraft depends on.

So, in summary, it's rare, they don't even know why it happens, and there are currently 1,477 other issues all demanding their attention. It should be little wonder that this, or any other particular issue, hasn't been fixed yet. 714 of the issues on the tracker are marked fixed, so it's not like they're sitting around doing nothing. They just have to prioritize.

I can shine a light on why we haven't fixed a glaringly clearly annoying bug .... we cannot reliably replicate it ... so ... no way to test :'(

I hate it, you hate it, I hate it even more.

Right now we're looking at really weird 'it only happened once' situations which can because by SO many different things.

If anyone can produce a clearcut testcase that has a >20% replication rate we can actually look into it.

I'v done some digging and I may have found what is causing this Bug.
Ever sense 1.3 the autosave function when you pause the game went missing. I downgraded to 1.2.5 and I never had the world save bug on it (because the autosave was still on that version) but when I went back to the latest version I started to get the bug again. there has to be some connection. As far as replication of the bug I found a video of it not to long ago. I'll try to leave a link.

anywhy its nice to know that Mojang knows that the bug exists. that gives me a little relief.

Got the video (finally) http://www.youtube.com/watch?v=Kv-Sid8rcCg
Hope that helps.

Is there anyone on this thread?
I want to know if that was the cause of the bug. (look at last comment)
it would also explain its random ratio, sense the game is coded with another autosave that activates every 30 minutes while playing, that could be why some of what you build stays intact while the rest is deleted.
(please tell me I'm not talking to my self)
If any sees this can he/she tell me if this theory is correct. Thank You.

I have just encountered this bug as well. Been playing Minecraft for years, no issue, but on a new map my girlfriend and I made and play LAN on.

It happened the first time I built a nether portal. I died in the nether and upon return to the Overworld, a tower I built to be the "center" of our map was just completely gone. It appears to be any time one of us leaves and goes to the nether. I tried building a nether portal way far away on our map, think it happened where the nether portal was, but the tower disappeared again. Next I thought it might have to do with dying in the nether, but just tonight we went into the nether, didn't die and returned. The tower is gone again, the nearby Village has the strange textures being replicated upward thing you mentioned, and three full chunks of the rather large castle I made are gone as well.

All of the missing parts are back to the default seed value. part of the village disappeared in the same way.

So far though, it only seems to happen when we travel to the nether and back.

I can fairly easily replicate the issue (it happens at least 80% of the times someone visits the nether, presumably any trip to another world). I've also uploaded screen shots of it in my 1.5.2 world (All of which is a result of the last time the bug happened, our last trip to the nether on 5/8/13).

Yes, I keep a close watch on this error, 23 signed on to this error and 17 people are watching it.

When this error happened to me, my buildings were weeks old and no new construction was in progress. No Creepers were involved, No Griefers were possible, No Ambien-induced Minecraft Playing was possible.

Any blocks which were removed are replaced, any blocks which were installed are removed. I.E. Tunnels/pits/holes are restored, walls/fences/farms disappear, flattened hills are restored to their original height, etc.

This happens DAYS/WEEKS after these changes have been made, after multiple saves.
The only workaround I can think of to copy/backup the save data in a different folder as a back up each day you play.

I get this error every time I switch from a snapshot to a release (in my case 13w19a to 1.5.2)

Thanks @Chili Fries, I managed to fix this bug by deleting horse saddles in 13w17a patch before updating to a later snapshot.

With regards to Chili Fries statement, Please give the step by step to recreate this error.

When this error first started happening to me, it was before I knew about downloading new snapshots, for me it started in 1.2.5 when I was only playing the official release. I wasn't switching back and forth. But since then I discovered those snapshots (around 1.3 post release) and when I would switch to an older version this didn't happen
e.g. I had carrots growing on a farm surrounded by a fence, I went to an earlier snapshot and those carrots blocks went back to plowed ground and the carrots in inventory and chests just vanished.
So I am unsure about your assertion

2013-05-27_11.56.30 = Seed created in offline mode, when internet connection was down. showing partial castle and underground tunnel system.

This screen shot was after "online" log in and load of the world. which loaded with half the castle and most of the mountain missing.

2013-05-27_11.58.55 & 2013-05-27_11.59.03 Show a recreation of the seed with no "built" items in it, created in online mode.

What I expected to happen: single player game world is loaded as was left when logged out/saved in offline mode

What actually occurs:

This has occurred three times, for me that I've tried creating a world in offline mode, and logged in again to play online and found parts of the world missing including parts that I've built on. This is has happened once in the current version 1.5.2 and twice in the previous version. There are no mods loaded, at all. Cheats are on, and bonus chests are on.

This time:
Seed name is "syrnia' loaded in survival mode. but switched to creative mode to do the building (only cheat used all three times). Logged back in, once internet connect re-established to continue building and found half the mountain and surrounding area missing.
if my memory is correct, this is how it happened both times previously as well with same settings except in random seeds

Hope this helps.

As far as I experienced, I can say the following about the bug. I hope it can help.
1) Any chunk within my presence (or as far as I can see) was not restarted, when I logged first time after 1.6.1 update in my old world and everything was on its place (but it may be just a coincidence)
2) First time we noted the bug was after my playmate joined the game via LAN. She appeared about 500 blocks away from me (as she disconnected there) and whole the area within her sight was redrawn. Whole village and the nearby area. Actually the closest vissible "edge" was quite far about 16 chunks away and all the structures within the area was gone (NPC village redrawn, blacksmith contained horse armor).
3) From this point, every area we have build anything before was visited by me first, for the case the bug is somehow connected with LAN playmate presence in the chunk. But it seems it is not, as I found another redrawn area myself.
4) The another redrawn area discovered was a jungle temple (it contained a loot again, including a horse armor).
5) The last area redrawn I have found was a dungeon close the spawn point, the chest contained the horse armor.
6) I have also found many dungeons plundered before and not redrawn now. But as the horse armor (any type) only has a chance to be in a chest, it is possible the game redrawns only those area, where was a chest AND now the horse armor should be in the chest.

Of course it also can be just a coincidence, but every area redrawn I have found contained a chest with a horse armor.

So how to replicate it? Well, I suppose it's quite easy, notwithstanding I can't do that. Just get the old Minecraft (version and launcher as well) and create a world. Do some changes, the bigger, the better (and more visible) and try to build close to NPC villages with blacksmith, dungeons or temples. After that update to 1.6.1 and log in to the world. Look around for your structures missing and chunks redrawn (and the chests with horse armor).

There is a new interesting finding, the redrawn areas are squares with coordinates at multiples of 512 (32×32 chunks). If there is a forest on the coordinate, the cut line is clearly visible. As you can se on the uploaded map, since 1.6.1 update, everything was previously built on "redrawn areas" is gone, but green marked areas were keeped. I can't say if the other areas were redrawn or not as there was nothing remarkable.

Let me add my voice to those crying out for resolution of this bug. I will confirm it is still very much alive and well as of this date in PC version 1.6.2.

Specs:
OS: Windows XP SP3
Single Core cpu (older)
2G Ram
Game Mode: SSP
Mods: Optifine only (problem existed well before Optifine was installed)

I don't know why it's so hard for the developers to replicate this issue. I can almost guarantee there will be some degree of block/chunk reset nearly every time I exit and re-enter the game.

I find Minecraft to be an incredibly engaging game and contrary to the tone of this comment, thoroughly enjoy playing it. Having a bug of this severity persist for EIGHT MONTHS (at least) and through many versions is unbelievable. Skip the horses, colored clay and carpets for the moment and redirect those energies toward finding a solution... please! This issue strikes at the heart of playability and overall enjoyment. No one wants to spend hours doing whatever in the game, only to have it mysteriously vanish the next time they log in.

I don't know why it's so hard for the developers to replicate this issue. I can almost guarantee there will be some degree of block/chunk reset nearly every time I exit and re-enter the game.

Just because it happens to you doesn't mean it's the same for everyone else. If the developers can't watch it happen, and actually cause it to happen intentionally by following a step-by-step set of instructions, then it's incredibly difficult to figure out what's causing it and how to fix it.

Every computer is different. Even if they have the same hardware, and supposedly the same operating system, the versions of the OS, the drivers, the software that's installed, etc. can all be different. Different patches may have been applied, and different usage patterns can result in very different configurations.

It could be that the save process fails. It could be that the files get corrupted. It could be a loading problem. It might be Minecraft's fault, or it might be something else entirely. Java. A failing hard drive. Anti-virus software. The OS. Because it could be so many things, it's incredibly hard to track down.

What might be helpful is if someone could upload a world backup, made right before a play session in which a chunk resets. Particularly if paired with a post-chunk-reset save. Then they could compare them, and possibly reproduce it, if it's a problem with the files. So keep good backups, and if you experience this issue, and it keeps happening every time you revert to the backup, then upload it somewhere and link it here so they can examine it.

Can you suggest a free file sharing site? The archive I have exceeds your file attach limit.

There are two saves in the file ready for your developers to examine. Steps I took:

1. Opened first saved world
2. Added blocks to rail bridge
3. Dug tunnel through small hill
4. Exited (completely, via Quit/Save)
5. Opened second saved world
6. Noticed last few blocks of bridge missing as well as entire tunnel through hill.

There are two .PNGs in the .RAR as well, showing the tunnel/bridge taken immediately before exiting the first world and directly after logging into second. I hope this helps. As I mentioned, this happens nearly every time I play SSP.

How big is the archive? I have personally used Mediafire and 4shared, but there are a million or so free file sharing sites out there. 200MB is a common limit for free users, but there are sites out there with higher or no (size) limits.

Where did you get your second world? Did you make a copy of world 1 in between steps 4 and 5?

The archive is approximately 41M. Thanks for the info on file sharing sites, I've uploaded it to MediaFire. Here's the link:

http://www.mediafire.com/download/y5aq3b7soyd6dfo/MC-2548_ChunkSaveIssue.rar

Yeh, I should've put a step 4A when I made the second copy.

If there is something else I can do to help your developers nuke this bug once and for all, please let me know.

This has started happening to me with the 1.7 snapshots. My world is over a year old and I'm getting regenerated chunks for the first time now when testing 1.7 snapshots. I notice them when I return from the end sometimes, and it's easy to see because I have destroyed all the grass from my spawn.

I have just seen this in 1.7.2. I had explored an area previously in 1.6.4 and in 1.7.2, but then went far away. When I came back, one chunk had dramatically changed--it was about 15 blocks higher than before, with perfectly straight sheer sides. I found an old map of the area and examined it, and could actually watch the old terrain (snowy tundra) being replaced by the new terrain (extreme hills, I think). I suspect this is an instance of this bug, made particularly spectacular because it put 1.7.2 terrain in an older section of my world.

Happened again in 14w05b : http://puu.sh/6F5kJ/78d49a2b59.jpg

Also affects latest snapshots.

This is also happening to me at this time and is still occurring as of this morning, 7/3/14, in 14W27A

Ben Vitek.

Still occurring in 14w32d

Got the same problem with 14w32d and now with 14w33c, it seems that it has something to do with the latest snapshot but I don't know... But what happened to me, I'm working on an adventure map and every now and then when I came back in my world my villagers disappeared... And I'm not going far away or something, just staying in the spawnchunks and then they disappear... Also my potions (as items, they'll never despawn or get picked up by players) disappeared, but my written books with the exact same tags as the potions are still there...

Is this still a concern in the current Minecraft version 1.8.1 Prerelease 3 / Launcher version 1.5.3 or later? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.

This is still happening with 1.8.1 Pre-3

Reopened, thanks.

Same thing is happening with me now, to my old savefile. Worked fine this week, then suddenly one zone reverts after save-quit, sometimes even ingame.

MC-73772

Any update on the problem?

Its happening to the entire nether on my server, Would appreciate some kinda info or something.

Read up the comments, If you want or need it, my server files can and will be shared upon request. Mine is VERY reproducible . It happens EVERY time i exit the nether. Once in a while the entire nether is reset, but ALL the time at least a chunk or two is gone. EVERY TIME. Im running vanilla 1.8. If you would like the files then tell me how and where I should upload them to.

sometimes when i go thousands of blocks away and come back, the stuff i built is regenerated with the original terrain

Still happens in 1.8.3, and this is the first time its really affected me, I wonder if certain seeds are just more likely to redraw.

This seems to affect my world too:
Minecraft Server 1.8.4 under Win7, client on LAN under Win7

Steps:

• I created a world in single player (btw, the 4 worlds I created with 1.8.4 all start in a Taiga biome, weird?) and played a few hours in it

• I copied the world to the server folder to play it in multiplayer

• I connected from another computer (and I was the only player on the server all the time)

• at one point, I dug a very long tunnel through a mountain

• If I go back and forth all the way through the tunnel, the chunk at one end of the tunnel will consistently be regenerated from the world seed, discarding all my previous changes to the chunk.

EDIT: World data available to download, see this comment: https://bugs.mojang.com/browse/MC-2548?focusedCommentId=225913&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-225913

If you can reliably reproduce the problem, please, zip up your world, upload it somewhere, and provide a link so that the developers can examine it. The only way they're going to fix this problem is through sheer accident unless they can see it in action.

Here's my world: http://www.mediafire.com/download/aioa4fxuhyxotdm/world.7z
I will provide the coordinates where it happens later (I'm in a rush at the moment, sorry).

Alright, so my world data might be useless after all.
After shutting down the server to upload my world and restarting the server, my world data got reverted to a very old state and I can't reproduce the bug the way I did before.
So, the data provided is actually an old version of my world.

I will then provide all I did with more details:

• All computers are under Win7 x64

• I started from a new install of Minecraft 1.8.4 (nothing modified except player skins)

• I created a world in single player

• I built some stuff in that world

• I installed a Minecraft 1.8.4 server in a folder on my desktop folder (the desktop folder does strange things on Windows sometimes, could it be related?)

• I made a copy of the single player world folder to the server folder and renamed it "world"

• I started the server (after modifying the eula file)

• I installed Minecraft 1.8.4 on a laptop in the same LAN as the server, connected through wireless.

• I increased the allocated memory on the laptop to 3 GB since I had some issues when I tried to play shortly in single player (e.g. long delay for the world to update after destroying a block).

• I connected from the laptop to the server (using Direct Connect, the game doesn't show in the LAN server list)

• I also had some issues to connect (errors about invalid session): I deleted the session lock file and restarted all to make it work

• I played a few days in a row from the laptop without restarting the server (there was always a single player on the server at any time)

• After some time, I dug a very long tunnel (a few chunks long).

• After going back to my house then going again to the tunnel, I noticed the end farthest from my house was closed. I dug it again and noticed that the blocks would come back every time I would go back and forth between it and my house. I assume all changes to that chunk were reverted every time they were unloaded.

• I submitted my first comment here, then stopped the server to upload the world data.

• After restarting the server, everything in my world was reverted to its state when I first copied the (originally single player) world to the server folder (losing everything that was done in multiplayer, but not previous changes)

• I modified the chunk that was previously reverting and my house, I stopped and restarted the server: this time all changes were kept.

• The server GUI never displayed any message in the log/chat window.

So, to sum up with some interpretation:

• It seems my world was only changed in the memory and never saved on disk during all the first session of the server

• Changes stopped being saved even in memory at some point, even though they would still show as long as the chunk was loaded

• after restarting the server, the data is back to what it originally was but now changes are saved between server sessions (at least during the few short tests I did, the bug might come back)

I followed the steps that I mentioned above again (except using a single computer and without re-installing clean copies of Minecraft and Minecraft server) without reproducing the bug...
This time, I had no session lock error and the generated world didn't start in a taiga biome (for once).

This just happened in my creative mode world.

I got very lucky it didn't delete any valuable stuff.

Affects 15w33c. Will try to reproduce.

I've encountered something similar recently where a huge section of rail and torches vanished. They were above ground and raised, so it's not water related. I thought that was bad enough, but now a mountain I'd tunnelled through has reset, taking all my rail and torches with it. It wouldn't be so bad, but I'm talking about a few Km in total! 😞

Was able to reproduce in SSP, so it affects both single- and multiplayer. Steps to reproduce:

1. Open the wurstmineberg world in 15w33c (15w33b seems to be unaffected)

2. Enter the Nether through one of the portals at spawn

3. Take the eastbound minecart track (green tunnel) or teleport to 526 112 -16

4. Exit the Nether through the portal labeled “felis' and madmalik's base”

5. Observe that part of the Nether portal frame is missing, having been replaced by stone

6. Reenter the Nether through the same portal

7. Observe that you are stuck in netherrack

According to MC-89682, this still occurs in 15w40b.

I had that happen on an adventure map i was making. It destroyed all my command blocks and circuits.

I keep getting the same problem, I am playing in version MC 1.8.8, if you can help or need any more information, just say it, thanks!

@unknown: If you can provide steps to reproduce the issue reliably it would help.

The steps given above no longer work to reproduce the bug, both because the offending dogs which were located at felis' and madmalik's base have been edited out of the world, and because of MC-89928.

Fenhl: Sounds like you might have been experiencing MC-89699 or something related.

15w43a

Possibly caused by MC-10976. The bug described there was already present in minecraft 1.4.x

Also happens in 1.10.2.

I can confirm that this bug happens in 1.10.2.

@@unknown: 1.10.2 is already marked as affected. Please check the affected versions before confirming an issue.

Confirmed for 1.11.2

Still on 17w14a

Confirmed for 1.12

I have a world in which chunks are re-generated when opening in 1.13. It is repeatable, depending on what one does in the world before opening in 1.13.

The world is from my 1.12.2 Spigot server and chunks are being re-generated in a at least two areas.

World backup here:

https://www.dropbox.com/s/w8m9sb94n7uzb23/Bangsplat%20Minecraft%20LAN%20Party%201.13%20Test.zip?dl=0

Two areas where chunks are regenerated:

x1260 z-20 (glass platform up in the sky, plus nearby portal on the ground level)

x290 z-1455 (portal inside the mountain, plus large build)

If I open this world in 1.13 (Vanilla) and travel to either location, there are chunks that have been regenerated.

If I open the world in 1.12.2 Vanilla first and travel to either location before opening in 1.13 Vanilla, the location visited will load properly.

Don't know if this is a 1.12.2 thing, a Spigot thing, or a 1.13 thing. But as it only happens when opening the world in 1.13, and it may happen in places I'm not aware of, I am hesitant to update the server.

Please avoid commenting on this issue too much as it is not related to what you are experiencing and nearly 30 people will be noitified of each update.

However please note that per https://www.spigotmc.org/threads/bukkit-craftbukkit-spigot-bungeecord-1-13-development-builds.328883/

• • • • • Spigot 1.12.2 worlds must be converted using CraftBukkit/Spigot and NOT Vanilla.**

Please do not use Vanilla to open these worlds, you will lose the chunks due to MC-133855

Hello, I've just discovered this serious bug and since I'm also the creator for some tools for Minecraft 1.13, I can confirm that it occurs as soon as the world is optimized using the new 1.13 function inside the Edit menu, even without loading the world.

I don't really wanna make publicity to myself, but that I know this is the only map generator that almost fully supports 1.13, so if you need a tool to generate a map of the damaged zone, maybe it might help you:

https://www.minecraftforum.net/forums/minecraft-java-edition/recent-updates-and-snapshots/2894808-minecraft-1-13-new-chunk-format-fully-decoded-read

Several dozens of chunks (at least) get fully deleted (even it's biome infos) creating some weird circular pattern which I thought it had to do with the rendering distance, but now I'm sure it's not that. Also I made my map on 1.6.4, then ported it on 1.12.2, but only leaving 4 regions around 0, 0: from -1024, -1024 to 1024, 1024, the rest were deleted on purpose. I had no bug even on 1.12.2. All were fully generated and the proof is the original map made from the 1.12.2 version.

Clearly this is a 1.13 bug, and when the player goes to the deleted chunks, new ones in the 1.13 format appears, and I know that because it generated icebergs on some of them. Even a village appeared on the east side over a jungle, but only in the missing chunks, so the houses were split in half.
 

Here is a double world download with the original from 1.12.2 and the damaged from 1.13 and several maps to help in the comparison of even underground structures or biomes, also attached:

http://www.mediafire.com/file/891tastibymzayi/Jupisoft_-Seed-488963417782474398.zip/file

Please update it as soon as possible or at least warn the rest of users or they might loose their worlds forever. Thanks a lot for your attention and have a nice day.

Please create a new ticket, it is unlikely these 1.13 bugs are related to the one in this ticket.

Please stop editing your ticket - use the preview feature.

Each time you do, you cause emails to go out to almost 30 users - that's over 300 emails you have caused so far.

Is this still a issue in the latest version of the game(currently 1.13.1)?

If so, please add it to the affected versions, thanks!

Please test with the latest snapshot (currently 19w37a), as there have been many fixes in relation to chunk loading and file storage.

Is this still an issue in 1.15.2 or later?