I'm experiencing a similar issue from thread SolidWorks Addin not loading, however this is a 3rd party Add-In called XTract3D.
The Add-In was working and now no longer loads. The DLL is in the right location and the Add-In is working on 2 other computers besides mine. I am using Solidworks 2018 Service Pack 3.0.
- I have tried uninstalling and reinstalling as Administrator
- I have tried repairing SolidWorks
- I've tried removing all VC++ and reinstalling
- I've tried removing all instances of the Add-In from registry.
Any assistance would be greatly appreciated.