I found this kb article which is rather old:
Normally a full disk should not be an issue as older data is removed automatically from disk to make space for newer events.I would not advise to just delete logs. Perform a cpservice stop/start if you have not done that already and otherwise I would strongly suggest to contact McAfee support and create a support ticket.
Thanks for the reply Robert. I did stop/start cpservices. I also did open a case w/ support. I had a couple of update archives on the system, McAfee support had me delete them to see if things would kick off. Right now I'm waiting for processing to catchup and then will try the GUI again.