Avast claimed the same thing about my copy too. On this machine that version had been in use every day since the release notice or a day after. Because windows kept telling me that "JMRI is already running." every time I started PanelPro with either version 4.17.3 or 4.16 I decided to try uninstalling both of them and clean out the Program Files (x86) folders and reinstall them.
Version 4.16 reinstalled as expected but Avast got in the way and moved the 4.17.3 file to what it calls the Virus Chest. Even though I requested a review of that action, in fact twice, I have received no response. After two an a half days, I simply clicked, or maybe right clicked(?) on the Virus Chest link and instructed it to execute anyway.
No problems since then. By the way, the erroneous windows message about already running still reappears from time to time, but not always.
Cliff in Baja SoCal
Dave Barraza