Get opc tags in a new PC
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OPC or SQL? I assume you use the former to access xA?
Since 5.1 RevB and 5.0 SP2 RevE remote launch of the OPC DA surrogate using "Launching user" (which is default in Windows) do no longer work.
Hence; remote (DCOM launched) applications need adjustments to DCOM settings.
The Configuration Users's Guide have all the details.
For subscriptions (advise requests) bidrectional DCOM adjustments are required (xA need permission in client as well to perform/deliver OnDataChange requests to the client's sink)
I.e the surrogate server nowadays need to be locked down to a dedicated account; preferably not an admin account, especially not the service account that apart from being administrator in 800xA also bypasses any audit trail setting. I sincerely recommend to create and use dedicated, non-admin accounts for external access.