QuickOPC 2016.2 can crash during OPC UA COM read and browse calls when installed with Custom Install / Full Installation. The VB6 UAReadAndDisplayValue example reproduces the failure, while the corresponding DA examples continue to operate.
Identify the affected installation
The failure was reproduced on fully updated 64-bit Windows 7 and Windows 10 virtual machines with VB6 installed. An earlier QuickOPC 5.40.315.1 installation had operated correctly on one reported Windows 10 system before the upgrade to 2016.2.
| Installation or build | Observed OPC UA COM result |
|---|---|
| QuickOPC 2016.2 Custom Install / Full Installation | Read and browse calls can crash |
| QuickOPC 2016.2 Express install for .NET and COM (native) development | OPC UA COM operated successfully in the reproduced scenario |
| QuickOPC 2016.2 build 524.1 | Defect corrected |
Root cause
The Full installation includes the Embedded Assemblies component, but that component omitted the Opc.Ua.Configuration assembly. Express installation does not install Embedded Assemblies, which explains why changing only the installation method avoided the crash. The issue was therefore tied to installer component content rather than to the UA read or browse call itself.
Apply the workaround or corrected build
- Confirm that the failure occurs with OPC UA through COM after a Custom / Full installation. Use the existing application or the VB6
UAReadAndDisplayValueexample to reproduce it. - If an immediate workaround is required, uninstall the Full installation and reinstall using Express install for .NET and COM (native) development.
- For the permanent correction, install QuickOPC 2016.2 build 524.1 or a later build whose release lineage includes that fix.
Verify the correction
Repeat both an OPC UA read and browse operation through COM. Confirm that neither operation crashes, then run the DA examples as a control check. If the crash remains, record the QuickOPC build, installation type, operating-system version, edition, bitness, language, and installed OPC-related software before escalating through the vendor's official support channel.
FAQ
Why does QuickOPC 2016.2 crash on OPC UA COM reads?
The Full installation's Embedded Assemblies component omitted Opc.Ua.Configuration. The resulting installation could crash during OPC UA COM read and browse calls.
What is the workaround for QuickOPC 2016.2 COM/UA crashes?
Uninstall the Full installation and use Express install for .NET and COM (native) development. That installation path avoided the fault in the reproduced Windows 7 and Windows 10 scenarios.
Which QuickOPC build fixes the missing Opc.Ua.Configuration assembly?
QuickOPC 2016.2 build 524.1 contains the correction. Verify the result by repeating OPC UA COM read and browse operations after installation.
