Libraries may be permanently deleted by right clicking over the small upper window in the Library that you want to delete from your disk and then choosing "Delete Library." Likewise you can open it as a document from the same upper window, right click over the file tab, and choose Delete. You may also delete the Library directly from Windows Explorer. If you delete it from Explorer while it is active in NoteTab, you will be prompted to save the Library when you exit NoteTab or switch Libraries. Choose "No" when that happens.