LabVIEW
Invalid Class String error when trying to access .ocx on Windows 10
Greetings LV Community!
To summarize the issue, when trying to open a connection to an .ocx object in a recently-updated version of a working LabVIEW application, we get an "Invalid Class String" error. We have tried all of the recommended remedies such as de-registering and re-registering the objects, checking permissions and Windows 32/64-bit settings. Everything appears to be ok with regard to these details, but this isn't my area of expertise, so there may still be some low-hanging fruit with regard to the configuration. Any ideas..?
This image summarizes the difficulty in the simplest terms.
Reduced to the most basic form.
Some background:
We have been asked to provide an updated version of a LabVIEW application that has been in continuous service since about 2013 on a Windows 7 PC. The application was originally written in LabVIEW 9 and migrated up to LV 2012 for the Windows 7 installation in question. This newest update cycle brings the code up to LV 2019 running under Windows 10 on a new PC. No other issues have been encountered other than this difficulty with the custom .ocx objects.
The Active X code was written by an OEM supplier, and powers an X,Y,Z motion gantry. Unfortunately, the original developer has moved on from the OEM, so this has turned into a bit of an "archeological dig of ancient software artifacts". (Based on the version history documentation, the first version of the OEM software dates back to sometime around 2002.)
In the OEM documentation there is a note indicating .NET v. 2.0 and Visual C++ Redistributable runtime 2005 were required (for the 2012/2013 version). We have run the installers for both of these, and they appear to have installed correctly. The OEM also provided a monitor application that calls the .ocx objects from a (non-LV) compiled executable. The monitor program also produces the same Invalid Class String error, so it doesn't appear to be specifically a LabVIEW error. However, since it is a problem that appears in LabVIEW, we still need a "LabVIEW solution".
Questions:
- Has anyone had a similar problem migrating an older LabVIEW application that uses .ocx objects to Windows 10?
- Does anyone have in-depth understanding of the inner workings of the .ocx call chain (circa 2012/2013), what parts are needed, and/or might be missing in a typical Windows 10 installation?
Thanks in advance for any clues you can offer!
-- Dave
