Try making a new connection to the new data source first so that there will be two data source connections. Then replace the data source. Data->Replace Data Source
Once the data source is replaced, then try replacing the field references.
This is lo~ng time discussion.
Couple of links.
These forum links and your reply instruct me to create the new connection to the data source first and then use replace data source. I'd try that if I could, but I cannot open the Tableau workbook without editing the connection to point it to a different data source. If I cancel the edit connection, my worksheets don't load in the workbook and I am unable to replace the references for any dimension/measure. Therefore, I can't activate vizes before replacing the data source. Any other suggestions?
I understand the situation. The link does not help in this case. Looks like the file lost the original data reference, which means to me, that you need to start all over unfortunately...
I don't have any idea to recover this. sorry.