I have investigated this and, somewhat contrary to what the error text says, determined to be harmless (in this particular instance - it depends on the precise error details)- it is basically a "false positive", a log entry that we should not be making in the first place. We will fix that in a future version.

If that is the only problem remaining, you should ignore it, and it will be safe to do so.

Best regards

Build 5.35.1173.1 resolves an issue which sometimes caused a deadlock inside QuickOPC resulting in (among others) ability to automatically reconnect. It can be part of your problem, I am not sure, but it's not a blind shot, it is certainly worth trying.

I strongly recommend using it, because there is a possible relation to your issue, and it won't make any sense to try analyzing a problem with software that is not up-to-date.

If the server is local, yes we can rule out network comm problems. But a server-side problem can still be present.

Best regards

Dear Sir,

first of all, I apologize for not replying to your post from April 24. We reply to all posts, but somehow this one got lost.

There are two issues in here: First is, why the problem does appear. This may, or may not be a correct behavior on the client side - it can (and likely, is) a genuine communication problem (or server-side problem( that the client cannot influence. And the second issue is, why the client doe not recover by itself.

As to the second problem, we have just recently fixed a bug that could be causing it - it was very similar. It is unlikely that you are using the build with the fix: It is 5.35.1173.1 (or higher), and it has been released around April 21. I strongly suggest that you download the latest build, rebuild your project with it, and retest.

As to why the communication problem appears in the first place: It is about a keep-alive mechanism, which requires the server to respond periodically, even if there is no data. It would be necessary to analyze on the protocol level (using e.g. Wireshark) to figure out precisely whether the server indeed has stopped publishing, or whether it is the client misunderstanding something.

The "Internal error": We will have a look at it, it should not be showing up. but as you said, it appears to be benign and is probably just a "false positive" kind of message.

Best regards

Regarding Windows Server 2008, our official requirements for QuickOPC version 5.35 (the crrent version) are Microsoft Windows Server 2008 R2 (x64) with Service Pack 1, and .NET Framework 4.5, 4.5.1, 4.5.2, or 4.6.

The edition of the server (Standard, ...) does not matter. You should be able to use QuickOPC version 5.35 as long as you have the "R2" operating system with SP1.

If you do not have that or cannot have that, it might still be possible to use QuickOPC 5.35, although it is not officially supported. The setup program will most likely refuse to install on such a system, but if you build your project elsewhere, the compiled application is likely to run well.

The last QuickOPC version to officially support Windows Server 2008 without R2+SP1 was 5.31. That is not going to get you far. I will send you a download link to it by email.

Best regards