…gen already exists but is not a source folder. Convert to a source folder or rename it [closed] Right click on the project and go to "Properties" Select "Java Build Path" on the left Open "Source" tab Click "Add Folder..." Check "gen" folder and click Ok http://stackoverflow.com/questions/6185600/android-fbreaderj-gen-already-exists-but-is-not-a-source-folder-convert-to-a-s