V9 (and later) Activation
The licensing system was improved in version 9 of the PDF-XChange family of products, and from January 14th 2021 it became necessary to activate license keys manually. Instructions on how to activate keys are available here. Please note that the XCVault.exe utility installed with all PDF-XChange products can be used to activate keys silently in versions 9.0.351.0 and later. Information on silent activation is available here.