yes, this is one of those cases where things *seem* to be counter-intuitive. Not so, really, if you look harder at it.
But my preference is to always use the positive if at all possible, just to make it clearer for me and those who follow. So I would have coded:
IF MOFFICE ='SN'
OR MOFFICE ='VS'
ELSE
error msg here
ENDIF

More typing but easier all around, in my humble opinion.

Cheers

JimN

>I was going to implement "IF MOFFICE <> 'SN' OR MOFFICE <> 'VS'" but I had to resort to "IF MOFFICE <> 'SN' AND MOFFICE <> 'VS'". The idea is to only allow entry of SN or VS, thus my reason for attempting to use OR instead of AND.