Troubleshooting

Most issues have a quick fix right in the launcher.

Each instance has its own logs on its page (the Logs tab). When something crashes, start here — the cause is often obvious.

The launcher reads the log, recognises a common cause — too little memory, the wrong Java, an unsuitable JVM flag, a missing dependency, a duplicate mod or a graphics problem — and offers a one-click fix. You can copy the log, or upload it to mclo.gs, which happens only after a second confirmation; tokens, UUIDs and your home folder are hidden from the record first.

The launcher downloads and manages Java itself — it picks the right major version per game and verifies the checksum. Runtimes are per-major, so versions don't clash. If something's still off, adjust Java on the instance's page.

Too little memory = crashes or stutter, too much = waste. The default is Auto (by mod count and the computer's RAM). Bump it for big modpacks, keep it low for vanilla. It is set per instance.

• Game won't start — check the assigned RAM and Java on the instance's page; look at the logs.
• Missing files / broken install — run the file check on the instance's page: the launcher compares mods (SHA-1) and repairs what is missing. Or reinstall the pack.
• A mod won't download — for mods whose author disabled downloads outside CurseForge, the launcher opens the file's CurseForge page in a window of its own, the page starts the download and the launcher picks the file up from Downloads and verifies it (see Modpacks & mods). If one mod still fails, skip it and add it manually.
• Linux: the window draws strangely — start the launcher with STYGION_SOFTWARE_RENDER=1 to bring back drawing on the CPU.
• Linux: signing in did not open a browser — the launcher tries every way a desktop opens links; when none works, it shows the address with a Copy button. Open it in a browser yourself.