QuickBooks error code 20 is basically seen when the new operating system puts the Hkey_Current-config\software key in the registry settings. As a result of this error, the user might not be able to send or print invoices and payslips. The QuickBooks printer not activated error code 20 is accompanied by an error message.
Thus, try reading the post carefully, or contact QuickBooks support team via our toll-free number for any sort of technical assistance i.e. 1-800-761-1787.