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  9. The requested OPC Data Access technology 'Com' is not supported.

The requested OPC Data Access technology 'Com' is not supported.

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19 Jun 2020 17:42 #8606 by support
Replied by support on topic The requested OPC Data Access technology 'Com' is not supported.
Thank you.

Here is the story: This is a problem in external library that we use so that OPC apps developed with QuickOPC do not need to be accompanied by installs of other related software. It looks like that the problem has truly started appearing windows Windows version 2004 update. I have reported it to the library vendor and we will see what the reply will be.

In the meantime, yes, please use the suggested workaround. But be aware of its limitations. Even though it works on your machine, it may not necessarily work on others, because the "prerequisites" might be missing there. So, using this workaround may trigger the need to install them manually. This is mentioned in the KB article, and the necessary prerequisites (such as OPC Core Components, or Visual C++ libraries) are in the main documentation.

Note that the documentation for QuickOPC 2012.2 points to obsoleted VC++ libraries, the proper sequence to install them is:

1. Visit support.microsoft.com/en-us/help/2977003/the-latest-supported-visual-c-downloads .
2. Scroll down to find the heading "Visual Studio 2015, 2017 and 2019".
3. In that paragraph, if you are on 32-bit machine, download and install x86: vc_redist.x86.exe . If you are on a 64-bit machine, install the previous as well, and *also* download and install x64: vc_redist.x64.exe .

Regards

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19 Jun 2020 17:15 #8605 by fbenitez-inblic
Replied by fbenitez-inblic on topic The requested OPC Data Access technology 'Com' is not supported.
Hello,

Thank you for the quick replay.

With this workaround I am able to read, write, subscribe, etc in all the different projects mention in this thread.

I will continue the development with this flags.

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19 Jun 2020 16:56 #8604 by support
Replied by support on topic The requested OPC Data Access technology 'Com' is not supported.
Hello,

an update on this: I was now able to reproduce something similar on one computer. Before I know more, can you please change your app.config once again, including this snippet:
<appSettings>
    <add key="OpcLabs.EasyOpc.Implementation.Native.Assemblies.EnableVC140RedistBoxer" value="false"/>
    <add key="OpcLabs.EasyOpc.Internal.OpcPSBoxing.EnableOpcCorePSBoxer" value="false"/>
    <add key="OpcLabs.EasyOpc.UA.Toolkit.ClientServer.UAClientEngineBase.EnableUACertificateGeneratorBoxer" value="false"/>
</appSettings>
You may think it is exactly the same as you are already doing, but it isn't. There was a typo: Before, in the first setting, there were Implementations (plural), now the final 's' is removed and there is just Implementation (singular). This mistake was on my side, I apologize (I have now also corrected the KB article).

In my test, this workaround resolves the problem (but it is just a workaround and I will have to let you know about its limitations, if it works for you).

And thank you for reporting the problem and giving helpful feedback!

Best regards

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19 Jun 2020 07:42 #8603 by support
Replied by support on topic The requested OPC Data Access technology 'Com' is not supported.
Hello,
I have updated to precisely the same Windows 10 version & build as you indicated, but unfortunately I still cannot reproduce the issue.

Questions:
1. Do you have antivirus or similar software installed? If so, can you turn it off temporarily and repeat the test?
2. Are you running 32-bit or 64-bit Windows?
3. Can you perhaps provide a virtual machine image manifesting the problem?

Regards

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18 Jun 2020 15:34 #8600 by fbenitez-inblic
Replied by fbenitez-inblic on topic The requested OPC Data Access technology 'Com' is not supported.
Thank you very much.
I have done some more testing, hope this helps out as well to find the root cause of it.

As I mention in a previous reply, I was able to read / write to any of the OPC Server (Kepware, TopServer and KitServer) using the third party library from Hylasoft. But if I create a EasyDAClient, even if it is not used at all, then I get the same error when trying to even connect to the OPC Server.

In this project (targeting Framework 4.7) I have both references, the Hyalsoft and OPCLabs, as long as I do not create an EasyDAClient, it works.
using Hylasoft.Opc.Da;
using OpcLabs.EasyOpc.DataAccess;
using System;
 
namespace TestWrite_OPCLabs_Hylasoft
{
    class Program
    {
        static void Main(string[] args)
        {
            // var easyDAClient = new EasyDAClient();    //If this line is uncommented, the Hylasoft client crashes the application in the same manner
            using (var client = new DaClient(new Uri("opcda://127.0.0.1/Kepware.KEPServerEX.V6")))
            {
                client.Connect();   //If the EasyDAClient is present, this crashes the application in the same way
                var tag = "Simulation Examples.Functions.Write1";
                client.Write(tag, 150); // Write Value
                var val = client.Read<o-bject>(tag)  ; // Read Value
                Console.WriteLine(val);
            }
        }
    }
}

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18 Jun 2020 07:33 #8599 by support
Replied by support on topic The requested OPC Data Access technology 'Com' is not supported.
Thank you. I cannot go further without reproducing the issue here.
I will try to install the Windows Update you have mentioned - please allow some time for it.
Will post here after I test with the Windows update.

Best regards

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17 Jun 2020 20:18 #8596 by fbenitez-inblic
Replied by fbenitez-inblic on topic The requested OPC Data Access technology 'Com' is not supported.
I have added the appsettings as suggested, unfortunately I am still not able to perform any action.
Attached is another video of it.
Attachments:

    Case-8593_...ings.mp4

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17 Jun 2020 18:49 #8595 by support
Replied by support on topic The requested OPC Data Access technology 'Com' is not supported.
Thank you for the video. Actually, there is some information about the program termination: - in the debugger output, it gives the exit code (0xC0000374), which seems to indicate heap corruption.

Can you please look at this: kb.opclabs.com/How_to_disable_prerequisites_boxing

and add the following to your app.config?:
<appSettings>
    <add key="OpcLabs.EasyOpc.Implementations.Native.Assemblies.EnableVC140RedistBoxer" value="false"/>
    <add key="OpcLabs.EasyOpc.Internal.OpcPSBoxing.EnableOpcCorePSBoxer" value="false"/>
    <add key="OpcLabs.EasyOpc.UA.Toolkit.ClientServer.UAClientEngineBase.EnableUACertificateGeneratorBoxer" value="false"/>
</appSettings>
Thank you

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17 Jun 2020 17:36 #8594 by fbenitez-inblic
Replied by fbenitez-inblic on topic The requested OPC Data Access technology 'Com' is not supported.
I am not able to step further in the debugger, the application closes and no exception is thrown.
I am attaching a video of it.

Case-8593.mp4

Attachments:

    Case-8593.mp4

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17 Jun 2020 17:24 #8593 by support
Replied by support on topic The requested OPC Data Access technology 'Com' is not supported.
Hello,
thank you for the additional information.

What happens if you step through the programmer in the debugger? Which statement causes the problem, and what behavior do you get in the debugger at that point?

Best regards

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  9. The requested OPC Data Access technology 'Com' is not supported.
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