On the two US Payroll windows, Print Checks and Post Checks, there is both a Process drop-down list and a Process button. To avoid confusion the Button is relabeled as RUN.
Navigation: Tools >> Setup >> Company >> Setup GP PowerPack
Mark the box next to TWK-UPR: Relabel Process Button as RUN, the click DONE.
The feature will be enabled for the current user. Other users must restart their Dynamics GP client to enable this feature.