A nbu to csv conversion is in most cases related to attempts of recovery of contacts from Nokia phone backups, in form of extraction of .nbu files and saving the contacts as .csv files.
Nokia NbuExplorer utility supports and can access several types of Nokia backup files, including .nbu files. It can be used to export and save various file type found in the archives, such as images, messages and even contacts, hence is an ideal tool to convert nbu to csv, i.e. recover contacts.
Updated: March 14, 2017