Hello.
I was able to reproduce the issue, but *only* on a computer that had multiple version of the product (or some left-overs from installations of previous versions). I was not able able to reproduce it on a clean computer.
I do not think that Excel version plays a role here.
Has the customer attempted it on multiple computers - and some that had not any QuickOPC/OPC Data Client before?
Things are generally difficult when multiple versions are involved, but in addition in some version we may have forgotten to update the references that are inside the Excel files, so they still specify some older versions of the COM type libraries of the product. When just one version is involved, Excel/VBA will use just that version, even if there is a version number mismatch. But when more versions are present, it can all get mixed up.
On a computer where I have seen the same or similar issue, here is what I did to fix it:
1. Open the file in Excel, but without running the code.
2. Developer -> Visual Basic.
3. Tools -> References.
4. In the list of available references, there will be one or two libraries starting with "OPC Labs..." checked. Remember/write down their down, and uncheck them. You may also want to hover over the "Location" at the bottom to see if they point to the right location (it has version# in it) - in my case, the locations were wrong.
5. Press OK to close the dialog.
6. Tools -> References (again).
7. This time scroll down until you find a block with "OPC Labs..." libraries. Check the boxes next to libraries that were originally references (e.g. OPC Labs Base Library Core, and OPC Labs EasyOPC "Classic" Library).
8. Press OK to close the dialog.
9. File -> Save...
10. Close Excel.
11. Open the file in Excel and test.
This has helped in my case. Hopefully it will help you/the customer too. If not, report that back to me (but it would be much more difficult then...)
