Install an FTB modpack on your server

Feed The Beast (FTB) packs such as Skies 2: Aero install from the Modpacks tab, straight from FTB's own servers, so there is nothing to download to your computer first. An install replaces the server's files with the pack's, so read what it changes before you press the button.

Checked against FTB Skies 2: Aero 1.13.0 and 1.14.0 (Minecraft 1.21.1, NeoForge 21.1.250 and 21.1.262) and our installer, October 2026.

Before you start

• Check the pack's RAM. Each pack's page on feed-the-beast.com lists what it needs. Skies 2: Aero asks for at least 6 GB of RAM, recommends 8 GB and runs on Java 21. A server's RAM is fixed by its plan, so compare the two first. How much RAM does my Minecraft server need? explains the sizing, and the Minecraft plans page lists what each plan includes. You do not pick Java yourself, because the panel sets it from the pack's Minecraft version.
• Keep a backup. The install window has Take a backup first ticked by default. Leave it ticked unless you have just made one. If every backup slot is already protected, the Backups tab says so and the install stops with an error, so delete a backup or remove protection from one to make room first.

Find and install the pack

1. Open your server and choose Modpacks under Content in the left rail.
2. Choose the Feed The Beast chip above the search box.
3. Type at least three letters of the pack's name. The tab lists up to 12 matches, each with its Minecraft version and loader.
4. Press Install on the pack. A window titled with the pack's name opens, such as "Install FTB Skies 2: Aero?".
5. Leave the version dropdown on "Newest that fits your server", or pick a release. The list holds release builds only.
6. Decide what happens to your world. With Keep my world, settings and player lists ticked, your world, settings and player lists stay. Unticked, the pack's world replaces yours.
7. Tick Start the server when it's ready if you want the server to boot by itself afterwards. It is off by default. If this server has never accepted Minecraft's EULA, leave it off and press Start yourself, because that is where the panel asks.
8. Press and hold Hold to Install and reinstall for three seconds, until it fills.

Open the Console to follow the install. It prints "Installing the FTB pack. This takes a few minutes." while FTB's own server installer works.

Start the server

When the install finishes, press Start. If the server has not accepted Minecraft's EULA yet, the panel asks for it when you press Start.

Settings from server.properties are in Config Editor. To switch on command blocks, for example, find Command blocks under Gameplay, switch it on, press Save changes and restart the server. If the editor says the file does not exist yet, start the server once so it writes one. Skies 2: Aero's server files already switch Allow flight on.

Moving to a newer pack version

The Modpacks tab updates a pack in place only for Modrinth packs, through an Update to button. An FTB pack never shows one: its card reads Up to date even when FTB has a newer version, and its Installed button in the search results is greyed out. One route is to take a backup, press Remove modpack, then install the newer version from the dropdown with Keep my world, settings and player lists ticked.

Remove modpack and the install each keep a protected backup named "Pre-switch backup". If every backup slot is then protected, the install stops with "Couldn't start a backup. Free a backup slot, or untick the backup and try again." Untick Take a backup first for that install: the backup Remove modpack took already holds your world.

If the install fails

A failed install shows an alert titled "The last install didn't finish" with Show install log and Retry install. Read the log first, because a retry reinstalls with the same settings.

• "Couldn't fetch FTB's server installer" means nothing was changed. FTB or our node could not be reached, or FTB has no server installer for that version. Try again in a minute, and if it repeats, pick a different version in the dropdown.
• "FTB's installer couldn't install this pack" means FTB's installer stopped part way. The log names the pack and version it tried.
• If the pack installs but will not start, read the crash report. Find and read a Minecraft server crash report shows where it is.
• A pack that is also on CurseForge can be installed from there instead. Install a CurseForge modpack on your server has the steps.