“Message: You cannot use Online Banking because QuickBooks is not registered.” “Error: The validation code is incorrect or the service is temporarily unavailable when activating.” It will display an error message on your screen that reads: In case the company file is damaged, or if you enter incorrect license information, then QuickBooks software will refuse to open and you might end up with a QuickBooks registration error. The file is encrypted for it carries the required information. To complete the installation of QuickBooks on your Windows 7/8/8.1/vista/10 you need to enter the correct license number and a product code.