Launcher problems

HMCL Warning: java.io.IOException: Self verification failed

What the log looks like

java\.io\.IOException: Self verification failed
org\.jackhuang\.hmcl\.upgrade\.UpdateChecker\.checkUpdate

How to fix it

  1. Download the official pre-built HMCL release (.jar or .exe) from the official HMCL website (hmcl.huangyuhui.net) or the HMCL GitHub Releases page instead of using GitHub Actions artifacts or self-compiled builds.
  2. If you are on Arch Linux or an Arch-based distro, uninstall the source-compiled `hmcl` package and install the pre-built `hmcl-bin` package from the AUR so official signing keys and Microsoft login support are preserved.
  3. Replace your existing HMCL launcher file with the official build and restart the launcher before attempting to sign in with a Microsoft account or check for updates.
LoadersVanilla, Forge, Neoforge, Fabric, Quilt
SeverityWorth checking
CategoryLauncher problems

Check your own log

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