Adding Additional Mods to your Minecraft Modded Server

When playing a Modded Minecraft server you may want to add mods to it to alter the experience or include something that you feel the pack is missing. Below you will find all the steps required to add the additional mods to your server as well as methods for using FTP access to update and restart everything.


  1. Installing Minecraft Mods on your Server
    1.1. First Checks
    1.2. Optional Steps
  2. Adding Additional Mods to Modpacks in Single-Player
  3. Troubleshooting
  4. Further Reading and External Links

Installing Minecraft mods on your server

First Checks

  • Make sure your server and local pack are running the same Minecraft version.
  • Make sure that the pack is running without problems before you add the mods.
  • Ensure that the pack version matches in your launcher and on the server.
  • Make a backup of your current World in case anything goes wrong.
  1. Stop your server.
  2. Connect to your server using the Multicraft FTP or your chosen FTP software.
    There are multiple methods for connecting with FTP. Read this for more information on using Multicraft:
    Using Multicraft FTP Access
  3. Upload the mod to your server through your chosen FTP access.
  4. Ensure it is uploaded to the mods folder or move it to that folder after uploading.
  5. Start the server.

Optional Steps

  1. If you wish to make adjustments to the mods configuration then stop your server again.
  2. Using your FTP connection of choice, open the configs folder and navigate to the configuration file that is relevant to the mod you just added.
  3. If there is a crash or problems loading check our Troubleshooting section below.

Sticky Note

Adding Additional Mods to Modpacks in Single-Player

There is another article available that goes through the process of adding mods to single-player Modded Minecraft.


When adding mods to existing modpacks there is a chance that something will go wrong, these are some of the most common issues that occur. Most importantly, following the First checks section above can prevent a lot of these problems.

Keep in mind that some mod authors will have customised and adjusted their pack to work exclusively or in a more integrated way with the mods that it comes with when installed and support for additional mods may not exist.


    at java.nio.Buffer.checkIndex(

This error may relate to an issue with the configuration files of the new mods. The quickest way to test this as the cause is to delete the configuration files of the mods that were added and then run the modpack again to allow new configurations to generate.

If this doesn’t work, the error is being caused by something else.

Firstly check the issue tracker, bug reports and comments sections for the mod to see if it is a common error or unique to you.
If you do not find a solution, open a support ticket with the mod author giving details of the error.


    at cpw.mods.fml.common.Loader.sortModList(

This error is an indication that either the mods list on your local computer and the server aren’t the same as each other or that the mods in them have different versions.

Usually, this error will be accompanied by a mod and version number. Make a note of this before checking your local files and your server files for that mod to make sure they match.

Occassionally a crash may be a little more in-depth and related to a specific mod being broken or some other more technical issue.
We always recommend checking the mod’s support, issues and comments pages to see if anyone else has suffered the error and potentially found a solution. As well as sending a message or opening a Ticket with the Mod author if a fix is not clear.

StickyPiston Support

Whether you own a server with StickyPiston or don’t, we are always happy to help with any technical issues you may be having. Open a support ticket with our team and we will be in touch.

Open Support Ticket

Further reading and external links

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