This is what I would recommend when upgrading from 6.4.
1. download the 6.5 server msi >>https://download.eset.com/com/eset/apps/business/era/server/windows/v6/latest/server_x64.msi
2. Run the MSI to do upgrade over the top by using the defaults. If you get some kind of access denied then you will need to enter database user name. usually era_user and password is located in >> C:\ProgramData\ESET\RemoteAdministrator\Server\EraServerApplicationData\Configuration
3. If you are running SQL Server express 2008 then you will need to upgrade that to 2014 at minimum. The all in one may do it. upgrades of SQL usually require reboot.
4. After reboot download the EP 8.x installer >> https://download.eset.com/com/eset/apps/business/era/allinone/latest/x64.zip
5. run the setup.exe and try the upgrade all components option now.
If any of them fail just uninstall and then do install from all in one. Tomcat may need full re-install.
Also if you are running Java 32 bit you will need to uninstall and install Java 64 bit >>
I notice on all installs of ESMC that the message in Status Overview always comes up in RED! "Notifications containing in accessible objects. " and has number. This is referencing the Notifications which do not have email address added to notification. Why is this the default especially if the customer is not using SMTP server settings to send out notifications? It throws off reporting. Is there any way to resolve this outside of adding an email address to ever single notification which I usually highly recommend not doing as it creates to much noise for the customer getting the notifications.