Hi QuickBooksDev-0076,
First, please check whether the framework version of the project is the same as the framework version of the dll you are referencing.
When adding project output, have you tried the "Locally-Copied Items" option?
And you could add it as an item to your project and set the Build Action to Content and the Copy to Output Directory to Always.
More suggestions you can refer to the following threads:
Visual Studio Installer Project does not include all dlls from output folder
Dependent DLL is not getting copied to the build output folder in Visual Studio
Best Regards,
Daniel Zhang
If the response is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.