You must grant ECL permissions so that users do not receive Execution Security Alerts when they use the Enterprise Vault client.
You must grant permissions to the following accounts:
The account that you use to run EVInstall.nsf
See Granting permissions to the account that will run EVInstall.nsf.
The Enterprise Vault Domino Gateway server account
See Granting permissions to the Enterprise Vault Domino Gateway server account.
If you intend to run NSF Migration, the Domino archiving user account.