Hello there, sally15.
The SDK that you are trying to open may have been compatible or defaulted to Enterprise version of QuickBooks. This can be the reason why it is opening the Enterprise.
We have a specific place called Intuit Developers Forum where customers, engineers, and product developers come together to discuss a variety of development topics and answer integration questions. I suggest posting this question on their page, so they can check or change the default version to open when running the SDK.
I've got some helpful resources to be more familiar with how QuickBooks Desktop SDK works:
If you have any other questions, be sure to let me know. I'm always here to help.