API: SolidWorks Add-ins and the Registry

Document created by Joyce Bossom Employee on Nov 17, 2010Last modified by Joyce Bossom Employee on Feb 28, 2014
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The SolidWorks add-in templates register your add-ins at compile time.


From a command window you can manually register your add-in with:


    regsvr32 yourDLL.dll

And unregister it with:


    regsvr32 /u yourDLL.dll

Most installation programs like InstallShield handle registration and unregistration for you.


The availability of SolidWorks add-ins is controlled by registry keys under:


The loading behavior of SolidWorks add-ins is controlled by registry keys under:



A value of 1 for the Default key indicates that the add-in is activated.

These keys should be removed when you un-register your add-in.

You can inspect the registry by typing in a command window:







The process of registering a DLL on Windows x64 is the same as Windows x32 with one exception:

On Windows x64, there are 2 views on the registry:

  • a 64-bit view, which is the real view
  • a 32-bit view, which is represented by a set of special keys in the 64-bit view that are named Wow6432Node


64-bit applications read from and write to the 64-bit registry view.

32-bit applications read from and write to the 32-bit registry view.


SolidWorks x64 is a native 64-bit application, so it looks for add-ins in the 64-bit registry view:

  • HKEY_CURRENT_USER\Software\SolidWorks\AddInsStartup


The 32-bit version of SolidWorks running Windows x64 looks in:

  • HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\SolidWorks\AddIns
  • HKEY_CURRENT_USER\Software\Wow6432Node\SolidWorks\AddInsStartup


To ensure that your add-in registration data ends up in the 64-bit registry view, please use the 64-bit version of the most common registration tools:

  • regsvr32.exe for COM dlls
  • regasm.exe for .NET assemblies registered for COM interoperability


Please refer to the attached screenshots (*.jpg) that show where to find the 32-bit and 64-bit versions of these tools. Please note that the 64-bit version of regsvr32.exe has '32' in its name, which might be confusing.


When installing an add-in using Windows Installer, please consult the Windows Installer user guide for how to set the target registry view for a registry entry.


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