Hello.

The code inside QuickOPC that deals with certificate folders does not distinguish whether it runs as Windows Service, or in Windows Forms, or in some other host.

I have done a quick test:
1. Simply created a new Windows Forms project under .NET Core 3.1/.NET 5+.
2. Added a button to the main form.
3. Added a code that reads a value from an OPC UA server and shows it in a message box (from www.opclabs.com/products/quickopc/opc-specifications/unified-architecture/generic-data ).

After running the program and pressing the button, it immediately creates a following directory structure under the directory where the program executable is (in my case, <project directory>/bin/Debug/net6.0-windows):

There would be more folders if a secure connection was actually in use.
Are you sure you are looking at the right place?

Hello,

I think there are two issues at play:

1. QuickOPC does not currently have any Windows Forms features under .NET Core/.NET 5+. This includes the "unsolicited user interaction" - in this case, the automatic pop-up that will ask the user whether he/she wants to accept an otherwise untrusted certificate. QuickOPC still works, but the certificates must be trusted by the regular mechanism, i.e. placed in the appropriate stores.

2. The (default) location of the certificate stores differs from that under .NET Framework. See:

- opclabs.doc-that.com/files/onlinedocs/QuickOpc/Latest/User%2...html#Certificate%20Stores.html
- opclabs.doc-that.com/files/onlinedocs/QuickOpc/Latest/User%2...ry%20Certificate%20Stores.html

The main piece of information, taken from these articles, that you are probably missing is: "In .NET Standard, the default certificate stores paths are all in directories that are located under the current working directory of the application." - i.e. not under a "common" place on your computer.

Best regards

Hello,

which QuickOPC version are you using please?

Best regards