Validation Rule to prevent 'Closed Won' Opportunities from being edited once a checkbox is selected by AR Team. Or should I change workflow?

Question

1. AND( $Profile.Name <> 'System Administrator',NOT(ISCHANGED(Opportunity_Closed__c)),OR(Opportunity_Closed__c = true))

Got no errors with this but it seems to just autocheck the Opportunity closed box vs disallow non-admins to edit the opportunity.

2. AND( ISPICKVAL( StageName , "4 - Closed Won"), AND( $Profile.Name <> 'System Administrator',NOT(ISCHANGED(Opportunity_Closed__c)),OR(Opportunity_Closed__c = true))

Tried variations with picklist value being closed won and opportunity closed = true

3. AND( ISPICKVAL(Stagename, 'Closed Won'), $User.Id != '005F000000431Qxxx1', $User.Id != '005F000000431Pxxx2', $User.Id != '005F0000005tuHxxx3', $Profile.ID != '00eF0000001B2gxxxC' )

Wondering if I just need to exclude users who can't or adjust our AP user to their own profile like the above?

Answer 1

So, the issue with "ISCHANGED()" is that it only looks for changes on the specific field it's referring to; if you want to lock the entire record (except for admins), I'd try something like the following:

PRIORVALUE(IsWon) && $Profile.Name <> "System Administrator"

(Yes, "IsWon" is an out-of-the-box Salesforce field, as is "IsClosed", but PRIORVALUE() is probably the important part here for your logic)