When you right click on a knowledge document in the Service Desk GUI and select "delete" you will no longer be able to find that document even if you search inactive documents. You may want to restore a document that was incorrectly deleted on your system. To this follow these steps.
To restore a knowledge document that was accidentally deleted by right clicking on it and selecting "delete" follow these simple steps:
Now you should be able to edit and access that document that was previously deleted.
NOTE: If you have purged knowledge docs using the archive/purge parameters in Service Desk, the document may actually be gone completely if it met the criteria specified for the archive/purge parameter.