How to Prevent Deletion Of Sales Order - Only if by end user?

samantha73

I'm trying to impement an event driven validation to prevent SO deletion however it also block base app deleting sales order after invoicing. How do I exclude system deleting?
The event:

[EventSubscriber(ObjectType::Table, Database::"Sales Header", 'OnBeforeDeleteEvent', '', false, false)]
    local procedure OnBeforeDelete(var Rec: Record "Sales Header"; RunTrigger: Boolean)
    var
        SalesSetup: Record "Sales & Receivables Setup";
    begin
        if Rec.IsTemporary then
            exit;
        if RunTrigger then
            exit;

Developer101

Hello, what do you require exactly? As I understood you want to prevent users to delete Sales Orders, is that correct?
What is NAV or BC version?