Bad news: There is no “Undo” button. So what do you do when this happens?

You have two options:

1. Since you deleted part of your runbook, you are probably still in “check out” mode with it. So, in order to see how the runbook was before check-out, log on from a different machine, to Orchestrator Runbook Designer. Select everything inside the runbook and copy it to a new runbook, then start modifying again.
2. If you just want everything restored in the same runbook, verify the time when you deleted your activities / links (let’s say it was 10:00 a.m.), then go to your Orchestrator database, and run the following query:

use Orchestrator

Select * from OBJECTS where Deleted = 1 and LastModified > ‘2013-11-22 09:55:00.000‘ and LastModified < ‘2013-11-22 10:05:00.000‘

Update OBJECTS set Deleted = 0 where Deleted = 1 and LastModified > ‘2013-11-22 09:55:00.000‘ and LastModified < ‘2013-11-22 10:05:00.000‘

In case you deleted the entire runbook, or worse, an entire folder of runbooks, you should check this post, which covers well the rest of the available undeleting tricks.