We've had a problem where we were unable to update enterprise manager to the update 4 version. Setup always failed to update and in the BackupSuite logfile we were seeing entries like
[31.01.2019 10:49:28][INFO] Exception occurred (Veeam products installation section).
Info: System.ComponentModel.Win32Exception (0x80004005): Fatal error during installation
at Veeam.Setup.MsiLibrary.VmMsiCommon.CheckError(VmMsiDatabase db, UInt32 result)
at Veeam.Setup.MsiLibrary.VmMsiCommon.InstallProduct(String product, String commandLine, Boolean& bReboot)
at Veeam.Setup.Wizard.VmInstallProduct.RunInstallation(Boolean& bReboot)
at Veeam.Setup.Wizard.VmInstallEngine.Install(ShowControlFunc showActionData, Boolean bRepair, Boolean bUpgrade, VmDialogEngineHandler m_dialogEngineHandler)
at Veeam.Setup.Wizard.PredefinedDialogs.VmInstallDialog.m_installWorker_DoWork(Object sender, DoWorkEventArgs e)
[31.01.2019 10:49:28][INFO] Starting services...
It turns out that the issue was caused by us running on our own SSL on the VeeamBackup Website in IIS. Veeam support switched it back to the self signed Veeam one, restarted the site and then the upgrade completed and were able to switch back to our SSL.
I had a similar error when upgrading Enterprise Manager from v11 to 12. It wasn't the certificate in my case. I basically had to disable UAC and run the upgrade as the local Administrator. Details are in post488158.html#p488158.