Problem:
When ClientAce is installed on a Windows Vista or higher operating system, the DA_Junction is unable to connect to an OPC server.

Possible Cause:
1. User Access Control (UAC) is enabled. Systems using ClientAce in a development and design environment should disable UAC to ensure that all components function correctly. UAC restricts objects' access to folders and files needed in the design phase; it does not affect these objects in the runtime environment.
2. The DA_Junction is making an OPC DA request to connect and browse for OPC items, but may not have proper permissions.

Solution:
1. Disable UAC.
2. Run Visual Studio as an Administrator.