[AccessD] Problem with an update query

I am getting a message "You won't be able to undo the changes this action query is about to make to the data in a linked table or tables. Do you want to run the query anyway?"

However, the only linked tables in the below query is YVIEW. I am not updating a linked table!

So then I click OK to run the query and get a message "Updating the data in a linked table is not supported by this ISAM"

How can I get past this?

UPDATE (YVIEW 
	LEFT JOIN TblCMF AS Cust1 ON 
		YVIEW.SITE_DUNS_NO = Cust1.DUNS_NUMBER) 
	LEFT JOIN TblCMF AS DOM ON 
		Cust1.MAS_DOM_ULT_DUNS = DOM.DUNS_NUMBER 
SET YVIEW.DOM_CUSTOMER_NAME = [DOM].[CUSTOMER_NAME];