Disable ability to Uncheck a checkbox

[Ryan L]

I want to add a checkbox that when it's checked will perform a specific action, but will only do it once per ticket. Is there a way I can make it so users are unable to un check the box once it's checked? 

[Alexey Matveev]

If you are on Cloud then you could do it without an additional add-on. You could create a transaction to change the checkbox and put the Value Field condition for the transaction.

If you are not on Cloud then I am afraid you need to use an add-on like Power Scripts or ScriptRunner.

[Sebastian Kleinholz]

You could extend your workflow by a transition that points to the original status. When pressing the button a dialog appears where only the checkbox can be set (and a comment, because the comment appears on every screen). When proceeding you are back to the original status. Now, to avoid that this transition is done a second time, a workflow validator checks if the checkbox is TRUE. So the transition will get 'invisible'.

It's important not to display this checkbox in any create or edit screen.