The file might be corrupted or have a double extension (e.g., .jar.txt ). Solution: Enable “File name extensions” in Windows File Explorer or use ls -la on macOS/Linux to verify it ends exactly with .jar .
If you want the genuine Meteor Client experience for Fabric 1.21, follow this official method. file name meteorclientmodfabric121jar new
Compare the SHA-256 hash of your downloaded file against the official release’s hash. ⚠️ Important Disclaimer Cause: The file might be
Bug fixes for new block interactions and updated UI elements for the latest version. ⚠️ Security Reminder file name meteorclientmodfabric121jar new