I'm having big Vlookup issues today as well... I've been banging my head against them for 2 hours now!

I have 3 spreadsheets (1) a list of preferred suppliers on them, (2) with every order we've placed and (3) with all the spend indvidual accounts.

Looking between (2) and (1) I've used

=IF(EXACT(F56,VLOOKUP(F56,'[Confirmed Preferred Vendor List 3rd December 2010 (Final)modded nh.xls]BBES - Final'!$A$2:$A$748,1)),"yes","no")

to tell me if a supplier is on the preferred list. However, I now need to do the same for a more specialist subset on (3). I've used the exact same formula but every single one has returned "no".

I added a line called "test" to sheets (1) and (3) which returned "yes", so I tried overtyping a value I knew was present in both sheets and still got "no".

Suggestions?