QBB File Extension Specification:Īs everybody knows, QBW file contains lots of important information related to accounting. QBB file format stands for QuickBooks Backup file. QBB file is the backup file of QuickBooks. However, file extension used by QuickBooks to save its data item such as finical records, logos, etc., is QBW file extension. QBB file extension is used by the backup file of QuickBooks, which is a money management application.