I can connect to the ODBC through an Excel workbook, but I cannot create the connection in PowerPivot. I get the message: "The test connection failed because the provider could not be initialized. Failed to connect to the server. Reason: ERROR [08004][Pervasive][ODBC Client Interface]Missing '=' in connection string.

Hi Joan_T,

This issue might occur if the Extended Properties information was not contained in the ODBC connection string.

The following is a sample of the correct connection string:

Provider=MSDASQL;Persist Security Info=True;User ID=sa;Extended Properties="DSN=MSSQL 2012;UID=sa;APP=Microsoft Office 2013;WSID=GENLI-T430;DATABASE=test;Pwd=**********";Initial Catalog=test;Password=**********

This KB article provides specific steps about how to create a correct connection string:
https://support.microsoft.com/en-us/kb/2971280 

Please refer to this KB article and try the method to create a correct connection string.

Hope it's helpful.

Regards,

Emi Zhang
TechNet Community Su