Hi,
Not sure which Forest Pack Pro version are you using now (the support for 3ds Max 2015 was added in
Forest Pack Lite/Pro 4.2.3), but I would suggest you to proceed the installation of the latest release -
Forest Pack Pro 4.4.1. There is no need of any special process (the installer will uninstall the older version automatically).
The installer can be downloaded from the
User Panel under
Downloads - My Products. To access it please log in to client site using your user details. The
Client login link you can always find on the top of
our website.
Hope that helps.
Best regards,