Troubleshooting the launcher

Fixes for the most common launcher problems: it won’t open, login fails, or a download breaks.

1. Launcher won’t open

   Confirm you downloaded it from files.foundrymtr.com. Allow it past SmartScreen (Windows) or Gatekeeper (macOS). Check the status page for known issues.

2. Microsoft login failed

   Sign out and back in. Confirm your Microsoft account owns Minecraft Java Edition and your connection is stable.

3. A download failed

   The launcher verifies every file and re-downloads corrupt ones — re-run it. Persistent failures are usually a distribution outage; check the status page.

4. Mods incompatible

   Let the launcher manage the modpack — don’t add your own mods to the FoundryMTR profile.