When accessing External Content Types in SharePoint Designer 2010, the error “The Business Data Connectivity Metadata Store is currently unavailable” was received.
When clicking on New External Content Type the error “There is no Business Data Connectivity Service associated with the current web context” was display.
The BDC service was started in Central Admin. The service application was also showing as selected in Central Admin >Manage Web Applications > Service Applications.
Since the web app was using the default associations, I tried creating a custom group from the dropdown and selected all the service applications.
Returned to SharePoint Designer 2010 and the External Content Types displayed.
Clicking on New External Content Type no longer gave an error and page to manage external content types displayed.