Here is the installer log showing errors.
Does this help anybody to understand what's wrong?
Thanks
Mar 17 22:19:19 ysteins-iMac Installer[3704]: Installation checks succeeded with warnings.
Mar 17 22:19:19 ysteins-iMac Installer[3704]: Installation check warning. An existing installation has been found on your system. NOTE: Detected an existing installation of ActivePython 3.6 on your system. Please consider uninstalling it before proceeding with the current
installation. Please check the documentation for more information..
Mar 17 22:20:04 ysteins-iMac installd[328]: PackageKit: ----- Begin install -----
Mar 17 22:20:04 ysteins-iMac installd[328]: PackageKit: Session UUID file exists - will not overwrite /var/folders/zz/zyxvpxvq6csfxvn_n0000000000000/C/PKInstallSandboxManager/7CCCE3A0-E6CB-40D6-8BDB-2B7B98F14FC1.activeSandbox
Mar 17 22:20:20 ysteins-iMac installd[328]: PackageKit: ----- End install -----
