Launcher problemsClassNotFoundException: net.fabricmc.loader.impl.launch.knot.KnotClient
What the log looks like
java\.lang\.ClassNotFoundException:\s*net\.fabricmc\.loader\.impl\.launch\.knot\.KnotClient
How to fix it
- Connect to the internet and launch the profile once in online mode so your launcher can download any missing Fabric library files.
- In Prism Launcher or MultiMC, edit the instance, open the Version tab, select Fabric Loader, and click Change Version (or Remove and Install Loader again) to rebuild the profile; in the official launcher, re-run the Fabric Installer.
- Delete the libraries/net/fabricmc/fabric-loader folder inside your launcher's main data directory, then start the game again to force a clean download of the loader JAR.
- Check the full file path to your launcher and instance—if any folder name contains an exclamation mark (!) or non-ASCII characters, move the launcher to a simple path such as C:\Games\PrismLauncher.
- If this happens inside IntelliJ IDEA while developing a mod, move the project folder to an ASCII-only path or set 'Shorten command line' to 'none' in your run configuration.
| Loaders | Fabric |
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| Severity | Stops the game |
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| Category | Launcher problems |
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Check your own log
