LabVIEW cannot load DLL

[MaSta]

Hello!

After not having used LabVIEW for some time and with a switch of my workstation to a Windows 11 based one in between, I now have trouble to get something working again.

What did I do?

1. On the old workstation, I had LV 2021 (32 bit) installed and there a set of VIs in a folder under \user.lib. The VIs each contained a CLN, for a DLL call. All was fine and loading and running.

2. Made a backup in 2024 of that folder in form of a ZIP file.

3. In January 2025 I got my new workstation, later installed LV 2021 (32bit) again.

4. Today unpacked the folder from the ZIP into the same location (i.e. same path) as it was before on the old workstation.

Now, when opening any of the VIs with the CLN, it cannot be run and LabVIEW says it cannot load the DLL. I even suspected a user permissions problem and changed the permissions for the DLL, but no chance.

Any clue what might be the actual reason? I cannot think if anything else. TIA. 

[GerdW · Accepted solution]

Hi MaSta,

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@MaSta wrote:

Now, when opening any of the VIs with the CLN, it cannot be run and LabVIEW says it cannot load the DLL. I even suspected a user permissions problem and changed the permissions for the DLL, but no chance.

Any clue what might be the actual reason? I cannot think if anything else.

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Does that DLL have any dependencies?

It's not just "load this specific DLL", but also "find all referenced dependencies"…

[cordm · Accepted solution]

The library probably depends on a driver or runtime. Open the DLL with this tool and see what its dependencies are: https://github.com/lucasg/Dependencies

[MaSta]

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@cordm wrote:

The library probably depends on a driver or runtime. Open the DLL with this tool and see what its dependencies are: https://github.com/lucasg/Dependencies

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That's it. Thinking about it, I remembered that the DLL was based on a package of CAN tools from a german company called ESD and that this package comes with an installer that most likely had installed the dependency DLL in the system without me being aware.