I need a validation rule on a multi-select picklist field that if a specific value is selected, no others can be selected.

Right now I have:

Includes(Multi_Select_Field__c, "Value1") 

But this throws the error when that specific value is selected, I want it to throw if that value is selected and the user tries adding additional ones. Hope that makes sense. Thanks!

2 Answers 2


Try this:

AND(Includes(Multi_Select_Field__c, "Value1"), PICKLISTCOUNT(Multi_Select_Field__c) > 1 )


Instead of trying to do this through a validation rule, it may be worth looking into turning your special value into a separate picklist or checkbox field and using that as the "Controlling field" to make your multipicklist a dependent picklist.

The idea being that when the controlling field is checked, you can configure Salesforce to disallow all values in your multipicklist.

Always worth trying to use standard features before trying to customize.

  • But wouldn't that require making 2 fields for the same idea?
    – stormy
    Dec 27, 2022 at 14:26
  • @stormy Yes, but this extra value in your existing picklist is already in a class of its own (it doesn't really "belong" with the other values). Breaking this into two fields (and this is screaming "I should be 2 fields" to me) also means you no longer need to worry about the implementation (you'll be able to take advantage of a feature Salesforce themselves provide).
    – Derek F
    Dec 27, 2022 at 14:31

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