Applicable Product : IJCAD 2014 and later
When the selected file has an external reference file which cannot be found, the message how to display/undisplay this unresolved external reference file will appear. If you don't want to display this message, select "Always ignore unresoved reference and continue" and then select any of the menu, "Update the location of the reference files" or "Ignore unresolved references and continue", to continue.
When you select "Ignore unresolved reference and continue", you can set again the reference target of the neglected and unreferred drawing file by external reference command.
※ If you want to display this message before opening the file, set the system variable XREFNOTIFY to "2".