This involves looking up data on a server.
I have this formula in numerous cells in column D of my worksheet. It tells me how many of $A74 we currently have in production and returns a zero if there aren't any:

=IF(ISERROR(VLOOKUP($A74,'K:\Customer Service\OOData\[OPENJJLU.xlsx]All Books'!$B$11:$C$2000,2,FALSE)),0,VLOOKUP($A74,'K:\Customer Service\OOData\[OPENJJLU.xlsx]All Books'!$B$11:$C$2000,2,FALSE))

Often, it returns the values from previous days.
For example right now it is returning 8 for this item, yet when I open the lookup workbook and look at what is actually in production for that item I find it in cell C13 and it reads 12.

If in my working sheet I postion my cursor at the end of the formula and hit enter ...the correct value is returned.

I don't understand this because my calculation option is Automatic
Other cells in the sheet that are looking up data from that same workbook and other workboods are returning the correct information.

I have repeatedly re-written the formula using the 'point to' method to ensure it connects to the right file etc., but to no avail...as I keep having this problem. Some days it works and other days it doesn't.

Our server group can't figure out what the problem is and keep telling me Excel is simply an unreliable tool to use to manage valuable programs.

I'm on W7 Pro, and we're on Microsoft servers.

Any ideas would be much appreciated!

Thanks