I should also note that the trial version of the component stops delivering valid data after 30 minutes of running; re-starting the host process gives valid data again. In this case, the trial runtime expiration will be indicated by an error or exception returned; in case of event notifications, they will still come when the data change, but the data will not be present and the Exception property of "event arguments" object will be filled in. The exception description contains a text that explains what has happened.
Are you checking the Exception property inside your event handler?

First thing is to try to determine whether the problem is specific to QuickOPC client. In order to help with this, I refer to a suggestion mentioned in the previous post:
Have you tried the same with other OPC client? Simply connect it and keep running....
Best regards,
Zbynek Zahradnik

There is no timeout. In fact it's the opposite of it - the component tries to renew the subscription even if e.g. the server goes down.
Have you tried the same with other OPC client? Simply connect it and keep running for days.
Best regards,
Zbynek Zahradnik