The Master Data Services add-in for Excel has Data Quality Services functionality to help you match data before publishing it to the MDS repository.  When you make a connection, if a DQS database is installed on the same instance of SQL Server as the MDS database, you will be able to view DQS buttons on the ribbon.  If the DQS_Main database does not exist on the instance, these buttons are not displayed and data quality functionality is not available.

But what if the DQS database is installed on the same instance of SQL Server as the MDS database, but the buttons still do not appear? Here is another reason you may not see the DQS buttons in Excel:

In the Master Data Services Configuration Manager, go to the Web Configuration tab and choose the MDS website.  At the bottom of that page you will see a button “Enable integration with Data Quality Services”.  Click that button and you should now see the DQS buttons in Excel.  But what if you click that button and get an error:

“Error while trying to enable integration with Data Quality Services.
SQL Server returned the following error: Windows NT user or
group ‘DOMAIN\MDS_ServiceAccounts’ not found.  Check the
name again.”

Run this SQL to fix this issue:

use [DQS_MAIN]
GO
IF NOT EXISTS (SELECT * FROM SYS.SYSUSERS WHERE NAME = ‘MDS_ServiceAccounts’) CREATE USER [MDS_ServiceAccounts] FOR LOGIN [SERRA\MDS_ServiceAccounts]
exec sp_addrolemember @rolename=N’dqs_administrator’,@membername=N’MDS_ServiceAccounts’

More info:

DQS missing from Master Data Services Excel Add-in