Hello,
After consulting the log file "kl-install-yyyy-mm-dd-hh-mm-ss.log", i found out that the previous antivirus was not uninstall completely, i had to remove manually all traces of the previous antivirus in the Regedit.
After removing everything, the installation was successful.
I also had the same issue on a brand new computer, after uninstalling the default antivirus apps, the installation was successful.
Honestly, you should personalize the error message that the software shows because it's mislead everything troubleshooting steps !
tjm65437 Did you check your log file ?