Upgrade Rapid Recovery Core to 6.4 failed with "ManagedBootstrapper.GUI.Setup.Exe" error.
Login to the core server to upgrade with the local administrator account and run the Core installer as administrator. If the core server Os is Windows Server remember to check if the installer is locked on the Installer file properties.
-Download PStools: https://docs.microsoft.com/en-us/sysinternals/downloads/pstools
-Unzip the PStools zip file.
-Open CMD as administrator and go to the PStools extraced folder from cmd: cd
-Execute the following command using the path where the Core installer is located at: psexec –i –s "C:\Users\useraccount\Desktop\Core-X64-18.104.22.1688.exe"
-Follow the Core installer wizard to upgrade Rapid Recovery.