I'm trying to advertise some software and I have a group of 4 machines. One of them says "No" in the "Client" column though and I'm seeing a lot of strange messages in the logs. Even though it says "No", it does have the client installed and it is checking policy regularly and installing updates. So how can it not be a client? Edit: Ok I checked the "All Systems" collection and the same client is actually in the system twice under the same name, one is a client, one is not. They have the same machine name, same IP address, but different discovery methods. How did that happen? And what happens if I delete the one that says it's not a client?

It's most likely that your client is installed, but it's GUID is listed under another record in SCCM. There's no way a client can check policies if it doesn't have a client installed. If the machine was renamed for example, it might still be listed in the database under the old name.