"Encryption key is invalid" when opening Visual Integrator after installing Sage 100.
Cause
Payroll is installed but not activated for the Company Code selected when Visual Integrator \ Main \ Import or Export Job Maintenance is opened for the first time.
In Sage 100 2019+ this can also happen with General Ledger being installed/activated but not set up.
Resolution
Activate Payroll for the selected company or change to a company code that has an active Payroll module set up.
In Sage 100 2019+ if General Ledger is not set up for company, select another company code or set up GL module.