Creating a Sharepoint site also created a Workspace

Hi，  michaelsh 

When creating a sharepoint site, you may have generated an Office 365 groups.

Normally, there is a one-to-one correspondence between office365 groups and classic workspace. When you create a classic workspace, an office 365 group will be automatically generated, and vice versa.

If you  want to block classic workspace creation,please check Power BI tenant setting " block classic workspace creation"  in Admin Portal . By default, it’s disabled

For more details,please refer to this document.

announcing-you-can-now-block-classic-workspace-creation 

You can also refer to this related thread.

https://community.powerbi.com/t5/Service/Office-365-group-not-creating-a-Power-BI-workspace/m-p/1311343 

Best Regards,
Community Support Team _ Eason