Most issues have a quick fix right in the launcher.

Logs

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

Java

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 in the instance detail.

RAM

Too little memory = crashes or stutter, too much = waste. Tune RAM per instance in the detail — bump it for big modpacks, keep it low for vanilla.

Common problems

• Game won't start — check the assigned RAM and Java in the instance detail; look at the logs.
• Missing files / broken install — reinstall the modpack; the launcher fetches what's missing.
• A mod won't download — for mods with third-party downloads disabled the launcher uses the official CDN; if one mod fails, try adding it manually.

In progress

• Crash parser — reads the crash log and suggests a fix.
• Repair — integrity check + fetch missing files.
• One-click log sharing (mclo.gs / a custom paste).