The path to the project group property files can be found in% USER_HOME% \ AppData \ Roaming \ NetBeans \ 7.2 \ Config \ Preferences \ org \ Netbeans \ Modules \ projectui \ groups. A list of property files with names corresponding to project groups in Netbeans will be here. To delete a project group, delete the associated properties file. Restarting Netbeans and infringing project groups should disappear.
Version 7.3 saves property files elsewhere.
Green source share