If you have existing installation of 4.0.1 on your system, please delete the LabPacks directory before doing the 4.2 P4 or 4.3 install.
If you don't do that you may get false virus warnings from some anti-virus applications.
They will detect the virus in the old executables that are in about to be overwritten with clecn version by the installer.
We are sorry for the inconvenience.
With best regards,