Minecraft FAQ/Errors Answered

FAQ

[WARNING] **** FAILED TO BIND TO PORT!

Possibility 1:
You have entered an external URL in the server.properties.
Solution 1:
Instead of using, the IP you got from http://www.whatismyip.org/, use the LAN IP of your computer (will start 192.168.. or maybe 10.0..), or 127.0.0.1 instead. If the server is yours, connect using whatever IP you've entered there.

Possibility 2:
More than one instance of the server software is running on the same port.
Solution 2:
When you set up the server, you probably ran it once to generate the map, then it closed. When you opened it again, the old instance was still running. Both are using the same port.
Close the server software. Ctrl + Shift + Esc to task manager Go to the processes tab. Sort alphabetically; look for all javaw.exe and end them.
Reopen the server software.

Connection Reset or general connection problem
YOUR SERVER:
You are trying to access a server on your own computer using your external IP.
Solution:
YOU must connect using the same internal IP you put in the server.properties file:
127.0.0.1:25565
into the client sign in screen. OTHER PEOPLE need to use an external IP address.

OTHER SERVER:
You are not connecting to the right port on someone else's server.
Solution:
Remember to put the port at the end of the IP address. Instead of "90.200.100.55" enter "90.200.100.55:25565" or whatever port they have given you.

[SEVERE]java.lang.ClassCastException: ...

Problem:
A part of the map can't be written.
Solution:
Close the server. Delete the folder containing your world data.
Close all open instances of the server (javaw.exe) using Task Manager, and then start the server back up.

java.io.IOException: Bad packet id <number>
Researching

Problem:
The client is sending a packet to the server which doesn't contain what it promises to. This raises an error on the server's side. It maybe due to a substantial difference in system clock time on the server compared to the client.
Solution:
Both the server and the client should synchronise their system clocks with time.windows.com:
Right click the time in the system tray. Click "Adjust Date/Time". Go to "Internet Time" tab, and apply common sense in order to acheive the above.

[INFO] Player1 lost connection: End of stream

Researching
Problem:
You're running Windows XP Service Pack 3.
Solution:
Run Minecraft on a Virtual Machine on your computer, or use one with a different OS. Sorry!

Kicking (IP Address): You need to log in!

Problem:
Your server.properties is invalid.
Solution:
Remove any extra lines you've added to server.properties. It should not contain, for example: verify-names, or grow-trees.

In Game Problems:

Q: How can I get a custom skin for my character?

A: To use a custom skin you must first pre-purchase the game. You can then go to the Preferences page, download the reference skin, edit it to your liking and finally upload your customized skin. You should now appear with your new look whenever you play.
Q: Can the water level change?

A: In short, no. The surface level of water in creative mode is set by the level of the ocean border surrounding a map. Water will fill any adjacent empty space and even a single water block acts as an infinite source that is capable of flooding everything at or below its height. Some custom multiplayer servers allow players to "build" both active and static water blocks, and it is also possible to add water to your own maps by using an editor.
In survival mode water acts in a slightly more realistic way and cannot create infinite floods. Water will drain downwards when filling a space below it and finite springs can occur throughout the landscape, above ground and below, that will dry up if their source is blocked up.
Q: What are the controls?

A: The controls can be found beneath the creative mode gameplay window and are customizable from the pause menu (accessible by pressing Escape).
Q: How do I save and reload my position (spawn point)?

A: When you join a server your spawn location is the default that the admin set. To change this, press Enter. This will save your current location so that whenever you press R you will respawn at this location instead of the server default.
Q: How do you make plants grow? They keep disappearing on me.

A: They must be planted on top of a dirt square and be in direct sunlight to live. Wheat will also die when it is trampled by mobs.
Q: Why does my building collapse / get destroyed on its own?

A: Sand and gravel blocks are subject to gravity - see below. New players not aware of this peculiarity may be confused and assume it is a glitch, or even a case of griefing, though that's not the case. It is worth noting that in custom multiplayer servers the "physics" behaviour of gravel and sand may be turned off, meaning they will not sink as normal. Beware, though - a server Op may turn the physics on later with potentially disastrous results for your work!
Q: Are the tiles affected by gravity?

A: Sand and gravel tiles will pour and sink into any empty space dug directly underneath them. All other solid tiles - dirt, stone, glass etc. - are not affected by gravity.
Q: What are the spawnable avatars (called a mob) in single player mode for?

A: No one knows, except Notch. They can however, be used for a number of imaginative games, although they have since been removed from multiplayer.
Q: Do the small plants grow into full trees?

A: Yes. They require a light, grassy area and some space. However, multiplayer servers may turn off the ability for trees to grow to prevent griefing.
Q: Who is this Notch guy I keep hearing about?

A: Notch is Minecraft's creator and developer.