A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
Hi, the problem is when the sheet is re-calculated if the workbook is closed it will give you an error, see here to read about sumif and sumproduct
http://xldynamic.com/source/xld.SUMPRODUCT.html#advantages
go to advantages of Sumproduct
try
=SUMPRODUCT(--('S:\Staff Shared Files\Board\WHRC Financial\Budget\MHRC\2012[11-12 Budget MHRC (Work File - Linked).xlsx]970 Sherb'!$A$7:$A$69=B18),'S:\Staff Shared Files\Board\WHRC Financial\Budget\MHRC\2012[11-12 Budget MHRC (Work File - Linked).xlsx]970 Sherb'!$S$7:$S$73)