error message - unable to save external link values
 

I have 2 spreadsheets that are linked - one calculates the data from the
other. I am not sure what is causing this error message since nothing has
changed in where the source is, and the source is always open when I use the
spreadsheet that does the calculations. It is on this file that I get this
error message when I try to save: "Excel canno complete this task with
available resources. Choose less data or close other applications." I click
OK and then get "Unable to save external link values". Its not done this
before today...how can I fix this?