Hi everyone,

Essentially, I have a custom object called Repair and I'm trying to have it so a user can create a new Repair record with Status either "Not Started", "In Progress", or "Completed" and save it, but the catch is that Status is a picklist value and when a user selects completed from the Picklist and saves, the field should either become Read-Only after saving or cannot be changed after saving.

I currently have: 
AND (
ISPICKVAL(Status__c, "Completed"),
OR (
ISNEW(),
ISCHANGED ( Status__c )
))

as the Validation Rule to prevent it from being changed after saving, and it lets me save as "Not Started" and "In Progress" but not when it is set to "Completed".

I'm lost and I've been going at it for awhile - any help is appreciated. I've looked at other posts that have come close to getting to what I need but I haven't been able to get around the issue of not letting me save AS "Completed". It's technically doing the opposite of what I want it to do.