Exclude e certain value from a Reference Dropdown

[sorin_mihai]

Hello,

I have a Category Table and a Projects Table.
The Projects table has a column named Project Category, which references the Category Table.
There are three rows in the Category Table and so in the Form of a project, the Project Category Dropdown displays these three values.
How can I make this dropdown display only two of these values? without erasing the row from the Category Table itself.

I tried putting this in the Valid if of the Projects Category column but it doesn’t work…:
[Project Category]<>“ValueNotWanted”

Thank you,
Sorin