Minecraft Java Modpack Manager: Failed to Extract Archive

The Modpack Manager sometimes stops with an error like this. It has been reported when installing ATM10 (All the Mods 10):

Failed to install modpack: modpack_manager: failed to extract archive: handling file: config/almostunified/unification/materials.json: filesystem: an error occurred: openat2 config/almostunified/unification: not a directory

The Modpack Manager’s installer stopped partway through unpacking the pack. The error comes from the installer, not from files already on your server. A failed attempt can leave partly unpacked files behind, such as a half-finished config folder, so don’t extract the pack straight over them.

Have Our Staff Install It

This is the safest fix. Open a ticket and our staff will clear the files the failed install left behind and install the pack for you. Contact our support team or open a support ticket with:

• Your Server UUID
• The name and version of the modpack
• The full error message from the Modpack Manager
• Whether there’s a world or any settings on the server you want to keep

Install the Pack Yourself

Most pack developers publish server files on CurseForge (ATM10 does). You can install those yourself instead of using the Modpack Manager. If your pack doesn’t have server files, see No Server Files?.

Stop your server. If it has a world or settings you want to keep, take a manual backup first. These steps leave your world folder where it is.

1. Download the official server files zip. On the pack’s CurseForge page, open Files, pick the version you want, and download the server pack for that same version.
2. Create a new, empty folder. In the File Manager, in your server root, click New > New Folder and name it, for example, pack-install. Then open it.
3. Upload the zip into that folder. With pack-install open, click New > Upload. The File Manager accepts uploads up to 100 MB. For a larger zip, use SFTP and upload it into pack-install. See Uploading a file.
4. Extract it there. Click the … on the zip and select Extract. See Decompressing a compressed file. If everything extracts into a single folder, open that folder.
5. Set aside any leftovers with the same names. Compare the extracted files and folders with your server root. If the root already has one with the same name, usually a config folder left by the failed install, rename the one in the root with Rename/Move in its … menu, for example config to config-old. Don’t delete it: if you had changed any settings, they stay in the renamed folder and you can copy them back later. Never rename or move your world folder. If you’re not sure whether something in the root is yours or was left by the failed install, open a ticket.
6. Move the extracted files into your server root. Select everything you extracted, but not the zip, then click Move… and enter /. See Moving files and folders. The File Manager won’t overwrite anything already in your root: if the Move window stays open, or something you selected is still there afterwards, something with that name is already there. Stop and open a ticket.
7. Install the matching loader. Open Server Options > Version and use the Edition Installer to install the loader and version the pack needs (NeoForge for ATM10). Leave Delete all server files first off, or it erases your world and the files you just moved in. If you can’t tell which loader version the pack needs, check the pack’s CurseForge page or ask us in a ticket.
8. Set the Java version to match the pack (Java Version Selection), then start your server.

Once the server runs, you can delete the pack-install folder.