Update links between workbooks

having an issue with updating links between workbooks, wondering if anyone has come across this and can help. Workbook 1 has all data, and Workbook 2 takes all the important data I need from workbook 1 by using a sumif function. My issue is that If I just open up workbook 2, all the data isn't there, it just has #value!. It's not till I open Workbook 1 while still having workbook 2 open that the data pops in there. So to sum up, both workbooks have to be open. my excel options are set to automatically update links, so I am not sure what is wrong. Any help is appreciated!