Minecraft Wiki:Issues

This page's purpose is to list all the bugs players have come across. Most of the single-player bugs also apply to multi-player.

Bugs and feature requests can now be logged at Getsatisfaction: Mojang.

Survival Single Player (SSP)

General

On some computers ^{[citation needed]}, the game will produce a .txt file containing an error message onto the desktop whenever the game is closed down. A similar error message is also produced when the game actually does crash.
If you have your Minecraft window open on full when you sign in the Mojang image will be out of place.
A glitch has been observed where, occasionally, a given area of blocks can revert to their original state, partially or completely undoing any construction or mining that had been done in that area. Usually this happens after a long excursion into one of the natural cave systems.
Seemingly related to the above glitch is one where a specific chunk will constantly revert. In chunks that constantly revert, water will not duplicate if it is flowing, and water tends to linger much like lava when the source is removed.
You are unable to directly swap items in your inventory when the two items are same. This is important if you would like to swap similar items with different durabilities.
Sometimes you can see through everything and it happens on all your games. Toggle the fog distance and everything will change back to normal (Default key is F).
Iron ingots and saplings may not appear in the inventory when collected.
If you wait a lot of time after map chunks are generated and then continue forward causing the game to generate new map chunks, the game will generate weird structures which do not connect properly with the map. Sometimes even creating mountains which are, in a sense, cut in half. Furthermore, if one chunk ends in an ocean, and the other starts off with land with an underground cave in it, the water will not enter the cave.
When sand or gravel is generated above a cave (or any opening), it will float until a space by it is modified in any way.
Sneaking does not prevent the player from falling off of Steps and Soul Sand. Soul Sand only prevents falling off when sneaking if the ledge height is more than 1.
Sneaking prevents movement onto Soul Sand from any other block.
Holding the Sneaking button then pressing the key to pull up the menu and quitting will result in being one block lower when the save is opened again.
Since the November 10th update, there have been several performance issues in SSP. Save/load times have increased, sudden random FPS drops, and random crashing/freezing.
Occasionally, when saving the game and reloading, you will fall through the block you were standing on.
A bug exists where the game may refuse to remember custom controls after updating (not to a specific version - just updating in general). This is caused by one of the values in Minecraft's "options.txt" file being unset, usually the "lastServer" field - attempting to connect to any multi-player server address (valid or otherwise) typically resolves the problem.
Occasionally, some chunks of the map do not update with the day/night cycle, as seen here. This bug seems more common with chunks containing snow biomes.
If you enter Fullscreen mode, then exit it, mouse clicks will no longer work for game dialogs (game menu, inventory etc). However, mining and using items still work. Pressing Esc, waiting for the game to save and restarting the client resolves this problem. Here is a topic on Minecraft Forums related to this bug.

Arrows

Arrows that hit doors can float if the door changes its state.
They also appear to collide with fences or portals.
Arrows that have not hit a mob become unobtainable if you die or save and quit then begin playing before retrieving them.

Boats

When entering a boat on ground it will show a splash effect similar than on water.
If you manage to stand on your boat while it is under water, the boat won't move to any direction.
If you go under a water stream your boat will accelerate and rise upwards.
If you save and reload while in a boat, you will no longer be in the boat.
Pressing F5 whilst in a boat will show your leg/foot armor protruding from the bottom of the boat, even though your character is sitting.

Cactus

If you place a door next to a Cactus it will clone the door giving you two doors (unlimited doors) shown Here.

Chests

Opening a chest whilst pressing a movement key, your character will continuously move in that direction until you open a chest again. This is also fixed by pressing the same movement key after leaving the chest menu.
Putting any item(s) in a large chest before quitting, opening it and putting the item(s) into your inventory, then pressing ALT F5 and opening it again will duplicate the item(s).

Dispensers

Unlike chests, when a dispenser is destroyed, the items inside are gone forever. Notch has stated that this is a bug: [1].

Doors

If you place a door next to a Cactus it will clone the door giving you two doors (unlimited doors) shown Here.
If doors are placed next to two stapled cactus-blocks, the door will immediately get destroyed and will drop two doors instead of one. One door can not be collected. If a door is placed next to two stapled and newly planted(small) cacti, an uncollectable door will be dropped, and a door window frame will remain, which drops nothing.

Fences

Fences on top of blocks will have all faces on its underside black.
Occasionally placed fences will become invisible [2]. They will become visible again if you place normal blocks near them though

Furnaces

If you exit your world while a Furnace is burning, when you re-enter, the Furnace's fuel will be full.
When destroying a Furnace, unlike Chests, anything inside the Furnace will be permanently destroyed.

Gravel or Sand

Gravel or sand will not fall down if a torch is placed between the time a block underneath is destroyed and before the sand/gravel begins to fall. Example
Gravel or sand will accumulate into resources if a torch is place between the time a block underneath is destroyed and during the time the sand/gravel is falling to fill in the spot. Example
Gravel or sand will not fall down if snow is underneath it.

Jukeboxes

Inserting a record and removing it before the song ends will cause the jukebox to eject a duplicate. Only one of the records will be retrievable, but the second will remain stuck in the world and eventually disappear after a certain amount of time. It is possible to abuse this bug to spawn hundreds of records.

Lava

When lava is touching the same corner as you it has a possibility of burning you. This will only happen when the lava is at the corner SOUTHWEST of you.

Example

   N
  =^= 
W +== E
  ++=
   S

= is a block + is lava ^ is you

Note: This can also happen with water

Minecarts

When spawning mine carts on a small track, they will gain momentum from colliding with each other.
Having too many minecarts will cause the game to crash.
It is possible to gain neverending speed for a mine cart from abusing the bug by spawning many carts on a small track.
Riding in a minecart on above track may cause your player's image to disappear until you die or reopen Minecraft.
Sometimes moving minecarts disappear completely.
If you drop a mine cart at the rail, will it still block moving mine carts at the track.
If you open your inventory while in a minecart, your player hand model will not function as expected.
Riding a minecart into a Nether portal causes you to become stuck.
Removing a minecart while riding in it will cause you to go through the ground, but only if the track is sitting on a non-solid-block and air is all around it. If there is an non-solid-block underneath the block the track is on, this will cause you to fall through.
If a minecart enters lava, the client will freeze. If the player is in the minecart when it enters lava, the client will crash.
If you make a cannon that can fire a lot of TNT and then place a single track facing away from the cannon on the "firing spot" (the place where you put the TNT missile), put a minecart on that track and detonate the TNT while in the minecart, you will fly up into the air (if you have god mode on) and when you come back, you will find more than one minecart item near the cannon. This has only been proved in version 1.2.2 and before.
Minecarts can go off tiny tracks if their momentum is too high.

Mobs

If a mob is riding a mine cart and 2 or more mine carts get stuck in each other, after destroying or moving the carts away from the other carts the mobs will be invisible.
When up close to a Zombie Pigman, the inventory GUI will become much brighter.
If you are above a Ghasts height and are standing still, Ghasts will shoot fireballs over your head, without damaging you.
Fireballs launched by Ghasts fail to start fire.

Paintings

If a painting is placed and immediately removed, there is a chance that the picture frame will get duplicated.
If a block is removed from behind a painting, it will pop off the wall when a player touches it after a reload, even if it is a multi-block painting and there are other blocks still behind it.
If there is a torch next of place you are going to put a two-block or more wide painting, the painting will go through the torch.
Sometimes the picture on a painting will be purple squares as seen in the terrain.png.

Portals

Placing a boat in the portal and entering it will cause the game to skip the "safe area" finding algorithm. This means that you will appear in the Nether world exactly where you are meant to regardless of blocks in the way. Example video.
Being killed in the Nether will cause a portal to be generated near your relative location on Earth, as though you had teleported back from your "final resting place" normally.
Riding a minecart into a Nether portal causes you to become stuck.

Reeds

Reeds can be placed on blocks that are not grass if placed on a water block. Example: http://imgur.com/AWW9b.png

Signs

Placing a sign on top of a block that is placed at the maximum allowed building height in the world will cause the client to crash.

Snow

Snow currently does not fall, meaning that once it's destroyed it will not come back.
Utilizing snow, one can place saplings and cacti on any block. The sapling will grow, however the cacti will break when they first grow.
Floating snow is occasionally found above "underground" lakes that formed on the surface of snowy biomes. (Update which caused this is currently unknown)

Stairs

Stairs let light pass through.
Double-steps will only drop one single step when broken.

Water

It is possible for multiple water currents to crash against each other and create an inescapable rip-tide. Not only will this rip tide hold you in one place, it will also throw you from a boat if you are sailing it.
While underwater, there a glitch allowing you to breath and see through water by placing blocks in proper ways. This video will show you how it's done
Like lava, when water is touching the same corner as you it has a possibility of colliding you.

World Select

On some Mac OS X Systems, the World Select screen will not appear at all, making the game unplayable on those Mac systems, in other cases, the Mojang AB logo will appear green and the title screen and the game in dark areas will appear red.
In dark areas some sides of tile blocks will not render making a see through cave and grass in daylight will appear purple, water in darkness will also not render. This has only been proved with non-intel chip Mac.
Once the player has entered The Nether, the save file will appear as 0.0 MB (or something similar). Some worlds will even have negative file sizes (such as -0.02 MB).

Survival Multiplayer (SMP)

General

If a player has respawned, he can place blocks on the block he is currently standing on. This will not decrease the block count in his inventory, effectively cloning blocks.
Full server world saves do not reliably save the entire world. This can be proven on a single person private server with whitelisting enabled when attempting to do a full server save via:

Disabling incremental level saving with 'save-off' on on minecraft console.
Forcing a full save to disk with 'save-all' on on minecraft console.
Archiving and saving the archived world with 'tar -xvzf save.tg world' on shell in secondary system console.
Turning back on incremental level saving by doing a 'save-on' on minecraft console.

Enormous, cuboid areas of unfinished map open in random places. Caves, minerals, water, magma and mobs are visible when a Player peers into one of these voids. These areas cannot be walked on, causing a "[user] moved wrongly!" message to appear in the Server, however, Players can ride minecarts through them with relative ease. If the void appears in the middle of water, Players can "float" over the void using a boat.
Blocks do not give items immediately when they break (this is probably caused by lag).

Arrows

Arrows shot onto a wall cause the arrow to create a flickering wobbling repeat of the arrows movement. This happens mainly on glass.
Fired arrows will appear to come out backwards at first, then continue on a regular trajectory.
After firing an arrow, any other player will see a repeating rapid arrow fire at the state the arrow was fired. However, the arrows will not collide and damage anything. They will be gone if reconnecting. Dispensers wont do this, though.

Boats

Boats greatly increase server lag.
If you ride a boat over a chunk of water which did not load properly ( ex. the water is really there, but you can't see it and can see through the whole world ), the boat disappears.
You can ride boats onto land but of course very slowly.
When going forward, boat goes sometimes backwards, but it's because of lag.

Chests

Destroying a chest will spill its contents and every item in the chest will be duplicated. Only half of the items visible to the player can be picked up, so no items are gained nor lost in the process.
- The disappearing seems to be caused by the same bug just in the opposite way. Instead of the server lagging behind the client and telling it that the item is still there the server will erroneously delete.

Dispensers

When a dispenser dispenses an item, there is no smoke puff and no sound is heard.

Doors

If you try to use /give command to give a door block to a player, the player will receive just the lower half of the door. If the player places it and breaks it, it will drop a normal door, as an item.
When attempting to stack doors, one will be deleted.
If you put two iron doors next to each other and add any mechanism to open both of them, the right one will be open all the time and close when you activate the mechanism.

Fishing

The fishing line is invisible.
Sometimes when fishing you won't get a fish when you right click to catch the fish.

Fences

Stepping on a fence is counted as an illegal operation. Any player who walks on a fence will get stuck on it. It is possible to jump off by using well-timed jumps, although this takes several tries. This usually causes minor lag(step-backs, freeze, background image cloning an object) to severe lag(rollbacks(inventory - lose items, double damage to tools, still damaged when other rollback occurs / blocks - re-placed, causes tools to still take damage, have long times to pick up/drop items), massive chunk errors, disconnects, server shut down in very severe cases).

Jukeboxes

Sounds of heavy bass, Or no effect at all.

Minecarts

Engines consume coal but do not move under their own power, making them useless.
Minecarts that pass over pressure plates will sometimes not activate a redstone current, even though a "click" noise is heard.
A player will pass through the minecart, but when the player is passing through it counts as "pushing" the minecart.
Empty/Storage Minecarts start to behave strangely when they are too far away from the Player. They disappear completely, disappear until Players disconnect and reconnect, or suddenly stop on tracks despite having sufficient momentum.

Mobs, Hostile

Shooting animations (Ghast fireballs, Skeleton arrows) are not visible.
The Ghasts' fireballs occasionally do not explode, only lighting a small area on fire.
Sometimes mobs freeze in animation and can not be hit. They disappear after about 2 minutes.
Some users are reporting mobs will be invisible, but can still attack you. On update 11/24/2010 SMP health update post Notch explained that to see invisible mobs, players must set their difficulty to the server side difficulty or higher.
Upon death, all monsters around you will be frozen when you come back. you cannot kill them, or attack them, and they cannot attack you. You can however push them, touch them, and they will still make noises. Skeletons, and Zombies will catch on fire, and it will flicker and not cause damage.
During severe lag, you can be killed by mobs or players without ever seeing them.
Mobs and other players will not take damage immediately when they have been attacked.
Mobs and other players movement is lagging. They can suddenly attack without making an attack animation.
Hitting a mob a few times in a row before the mob receives the damage will cause the mob to receive the damage from only one hit, but the force of all of them, making them fly up and backwards a considerable distance.
Every type of a mob will freeze, when the server is timed out.

Mobs, Neutral

Squids can rise upwards the sky and disappear behind the clouds.

Paintings

When copying an SSP world onto an SMP server, paintings are removed in the transition.

Sand and Snow

Sand will not fall down if snow is underneath it.

Stone Buttons

In addition to not triggering doors, stone buttons may jump from the wall they are actually placed on to the one opposite upon being pressed the first time if there is just one block of air in between. They can then not be removed reliably without also removing the block to which they are attached.
Triggers aren't doing any sounds in general.

TNT

TNT lit by one user cannot be seen by another.
Occasionally, a TNT block meant to drop will enter a repeating fall animation (but not actually fall) when lit. When the TNT finally explodes, it will explode at the position it was placed.
Occasionally, a TNT block can also explode twice, but this will not damage the environment twice.

Trees

Planting a sapling and waiting a bit will sometimes yield tree trunks with weird distributions of leaves, and in some cases, no leaves at all. Trees can also grow but be invisible, making it impossible to traverse a tree farm after a while. Rejoining the server appears to make invisible trees visible again and fire will swiftly cause phantom foliage to be made manifest.
Foliage from trees will overwrite some blocks(such as a nearby fence)
Placing a torch on foliage does not make the 'pop' sound for the item being placed.

Water

While underwater, there a glitch allowing you see through water by placing blocks in proper ways. This video will show you how it's done. It will appear as if you can breath under water and your breath meter will disappear, but you will still drown.

Wheat Seeds

Crouching/Sneaking over tilled soil does not prevent it from becoming trampled. Same goes for planted seeds, etc.
Occasionally, patches of planted seeds will revert to a regular dirt block without any physical contact.