Yesterday we released the 10th beta – and very likely the last before the gold release. One of the changes was the addition of two exports in Win32.lib; GetProcessID and SetProcessorAffinityMask. From emails sent into support we know that at least 1 (possibly more) 3rd party tools ship a .lib file with those same exports. That means you’ll get duplicate symbol errors if you use one of the 3rd party tools that export those symbols. We are getting in touch with all 3rd party devs to alert them those entries need to be removed from their .lib files.
In the meantime, if you run into the errors it is very easy to use LibMaker to remove them. Support staff made a ~1 minute video that walks you through it.