We have a number of old DNS entries in our forward lookup zone. Some dating back to 2012 and 2013. We have enabled "Aging and Scavenging" and had it kick off last night around 7pm. It has ran a few times since then as well but when I check the even viewer on the DC/DNS server I get event ID 2502 with the text below. How can I get this to run properly and clean up all the crap that is floating around in the forward lookup zone?

The DNS server has completed a scavenging cycle but no nodes were visited. Possible causes of this condition include:

 1) No zones are configured for scavenging by this server.
 2) A scavenging cycle was performed within the last 30 minutes.
 3) An error occurred during scavenging.

The next scavenging cycle is scheduled to run in 7 hours.

The event data will contain the error code if there was an error during the scavenging cycle

Are they static entries?

The entries we are trying to scrub are not static. There are static entries in the forward lookup zone, which is fine, but there's a lot of trash floating around in there. Multiple entries for machines that all show the same IP or entries for machines that were for users who are no longer with the company. Those machines were re-imaged, re-named, and assigned to other users but there are still entries showing up in the forward lookup zone.

What server OS version and what domain functional level?

Does this apply? Are you backing up your zone hosts files daily?

DNS Scavenging not working

Past that - no clue.

You enabled it on both the server node and zone level right?

Also you said you kicked it off at 7pm - I take it you did this manually, right after configuring scavenging. Take a look at this KB from MS that explains your problem:

Yes, on the server and zone.
I just read the KB you linked to. Interesting. That definitely sounds like our issue. Our next date we can scavenge is sometime on Saturday. I guess I'll just have to wait until Monday to see if it works.

My experience is that this can actually take several weeks before you actually notice old entries being scavenged. If you've got more than one DNS server, just set up scavenging on one of them, then let AD replicate that out to the others, dont set up scavenging on all of them.