How do I set the startup jar/script and fix "invalid or corrupt jarfile" errors?

Your server launches whatever file the startup settings on the Settings page point to. When you see "invalid or corrupt jarfile," it almost always means that target file is either the wrong name or was damaged during upload. Here's how to point your startup at the right file and clear the error.

Why this happens

The Settings page holds a variable that names the exact jar/file the server runs at boot. If that name is wrong, or the file itself is incomplete (a half-finished upload) or empty, the server can't launch it.

Fixing the startup file

1. Open the Settings page and check the server jar/file variable points to the correct filename.
2. Switch to Files and confirm that file actually exists and isn't 0 bytes or a partial upload.
3. Re-upload the jar if it's corrupt, or for Minecraft reselect the correct software on the Software page.
4. Restart from the Console tab.

Warning: "Invalid or corrupt jarfile" nearly always means an incomplete upload or a wrong filename. Re-upload over SFTP and double-check the exact name on the Settings page.

Tips & best practices

• For Minecraft, prefer the Software page over manual jar uploads — it installs the right file and sets your startup for you automatically.
• Upload large jars over SFTP rather than the browser for a more reliable transfer.

Frequently asked questions

The jar name has spaces or a typo — does that matter? Yes. Match the variable on the Settings page to the exact filename, character for character.

Where do I set RAM? Also on the Settings page — see our performance articles for the details.