There is a windows utility for the client "HarCompare" that does exactly that - compare a local directory (folder) contents
with what is in the Harvest repository based on Project and State. It will provide basically three(3) reports...a report of files in the local folder that is not checked into Harvest; a report of files that are local with differences compared to what is in Harvest; a report to show list of files that are local that are the same as in Harvest. You can find it here:
https://communities.ca.com/thread/241745212