.QBB files are backup files of financial data that has been created by QuickBooks money management software. The QBB file will contain a full backup of company (or personal) financial data, any templates, logos, letters, and images used in your project. The QBB file is often used to restore the original data in case the primary .QBW file is deleted or corrupted, or to transfer data to another pc or user. The file extension may need to be changed from ".qbb" to ".qbw" in order for the file to open correctly in QuickBooks.