The Business Data Connectivity Metadata Store is Currently Unavailable in SharePoint 2013

In this article you will see how to resolve "The Business Data Connectivity Metadata Store is currently unavailable" when trying to create an external content type using SharePoint Designer 2013.
 
Problem
 
In SharePoint Designer 2013, when I clicked on "External Content Types" under the left navigation I was getting an error as shown in Figure 1.

Figure 1: Create external content type using SharePoint Designer 2013
 
This is because either the BCS service application is not created or it is not associated with the web application.
 
How to resolve:

1. Open "Central Administration".
2. Click on "Manage web applications" which is available in the "Web Applications" section.
3. Select the web application and then click on "Service Connections" which is available in the ribbon interface as shown in Figure 2.
   
   
   
   Figure 2: Associate the service application
    
4. Select the BCS service application and then click on Ok.
5. Now you will be able to create an external content type in SharePoint Designer successfully.

Summary
 
Thus in this article you have seen how to resolve "The Business Data Connectivity Metadata Store is currently unavailable" when trying to create an external content type using SharePoint Designer 2013.