MCreator issue tracker has been migrated to GitHub.
Existing tickets have been migrated to GitHub. Please open new tickets on the GitHub tracker instead. If you do not have a GitHub account, all feature requests and bug reports from forums are still considered and checked by the maintainers.
1: You have two mods with the same name. Check which two mods cause this.
2: You can't use the installation from an old computer on a new one. The best way to recover a workspace would be to reinstall the same version of MCreator as you used on the old computer on the new one, copy the forge and user folder from the old computer and replace the folders in the new installation with these from the old computer.