Using the UA sample "Client Full", I am getting an exception (UnifiedAutomation.UaBase.StatusException) saying "Certificate is not trusted".
The exception is thrown and caught in the program's MainForm, and I do not see the TrustCertificateDialog as expected.
I have exported the certificate and added it to the Trusted Root Certification Authorities store.
The exception message includes the thumbprint, which I used to check that the certificate is in the store.
(By the way, the program I'm connecting to, and from which the certificate was exported, happens to be Industrial Gateway OPC Server)