title: OPC UA Client - Tag Group shown as empty when it's not
body: <p>I'm writing a UA Client DLL to allow the querying and reading of OPC tags. I've previously written a DA version, but now the time has come to move with the times and leave the DCOM hell-hole alone.</p>
  
  <p>All's going well, but I've noticed I'm unable to browse to certain tags which I <strong>know</strong> are valid and in the OPC project. My browser search of the container node of one of these tags reports that it contains no nodes and an exception is thrown, but the group and the tag it contains can be browsed by DA process. Even the Sample UA Client app provided by the OPC foundation, does not list these tags. For example see below:</p>
  
  <p>The tag group in question is "TKPlant.CL535E.Global.iaHomg_Press".</p>
  
  <p>In Kepware, the group has the following 6 tags:</p>
  
  <p><a href="https://i.stack.imgur.com/iN5Rl.png" rel="nofollow"><img src="https://i.stack.imgur.com/iN5Rl.png" alt="Kepware Screen Shot"></a></p>
  
  <p>In the OPC Quick Client the states and values of the tags are.... (all's good)</p>
  
  <p><a href="https://i.stack.imgur.com/13cKe.png" rel="nofollow"><img src="https://i.stack.imgur.com/13cKe.png" alt="OPC Quick Client"></a></p>
  
  <p>But in the UA Client Sample App, browsing shows the following:</p>
  
  <p><a href="https://i.stack.imgur.com/xd89p.png" rel="nofollow"><img src="https://i.stack.imgur.com/xd89p.png" alt="UA Sample Client"></a></p>
  
  <p>You can see that no nodes are believed to exist with this group. Node properties are :</p>
  
  <p><a href="https://i.stack.imgur.com/VdXNO.png" rel="nofollow"><img src="https://i.stack.imgur.com/VdXNO.png" alt="enter image description here"></a></p>
  
  <p>Compare this to a similar group:</p>
  
  <p><a href="https://i.stack.imgur.com/4Bm2d.png" rel="nofollow"><img src="https://i.stack.imgur.com/4Bm2d.png" alt="enter image description here"></a></p>
  
  <p>And the properties for this group:</p>
  
  <p><a href="https://i.stack.imgur.com/kEwX7.png" rel="nofollow"><img src="https://i.stack.imgur.com/kEwX7.png" alt="Group Properties"></a></p>
  
  <p>I can't see any differences, but it seems that the UA Sample Client is having the same results as my browse function - not seeing any tags within the group.</p>
  
  <p>I think the UA Client thinks this is a tag in its own right, not as a group. But this project is is actually on site and working. Curiously, when looking at the Quick Client screen shot, the group itself appears and is given a value???? - </p>
  
  <p><a href="https://i.stack.imgur.com/IHL0V.png" rel="nofollow"><img src="https://i.stack.imgur.com/IHL0V.png" alt="Tag Group has a value"></a></p>
  
  <p>I know this is probably a long shot, but does anyone have any ideas why this group - which does have tags -  is shown as empty when accessed using UA?</p>
  
  <p>Thanks</p>
  
  <p>Steve</p>