"Rules will only be run on items in mail folders"

Question

"Rules will only be run on items in mail folders"
I have a client that is trying to create rules in Outlook and she is the owner of a shared mailbox. Whenever she creates a rule for either one of the mailboxes she is also getting the "Rules will only be run on items in mail folders" error message and the
rules will not run. Previous rules did run Monday, but stopped on Tuesday.
The user deleted the rules and attempted to recreate them, but received the same error message. I noted the previous posts, copied the questions and answered them. Hope this helps.
1. How were the rules created? Was it created from Outlook or OWA  or any 3rd party tool?
Created in Outlook, not in OWA or a 3rd party application.
 2. Are these rules server side rules or client side rules
They are created client side and saved server side. Exchange Server is 2010.
 3. Are these rules set for public folders or folders under mailbox
Rules are on a mailbox that the user owns and on a separate mailbox that the user has owner control on.
 4. Were these rules working before?
The rules worked on Monday 11/19/2012, but stopped working the next day. The last software updates were on 11/15/2012
I also ran a repair on MS Office and the error message still comes up.

Answer 1

This thread is old but I thought I would add the information I have learned.
This problem all revolves around the option
“Enable Rules on all RSS Feeds”. 
You have to check that in order to run any rules against RSS downloads but when you do, you get that message. 
The option makes Outlook process the RSS Feeds folder which it normally skips (like Calendar,
 Contacts, etc) and the RSS messages coming in.  Although the RSS items look like regular Outlook e-mails, they are different and they are normally ignored unless that option is enabled.  Because of those two
things, you get the pop-up message – which is not an error - it’s telling you that it’s can’t process non-mail folders and messages.  You can usually fix it  by setting your RSS Feeds to download into a SUB-FOLDER of the RSS Feeds folder. 
Outlook actually want’s it that way and makes it hard to specify the root “RSS Feeds”. 
You will still get the message less often but it will have a checkbox with, “Do not show this message again”. 
Check that option because it’s just informative. and you should be all set.
I did the testing for this on Outlook 2007 not using Exchange.  If someone else finds a situation where this doesn't apply or work, poke around non-mail folders and see why Outlook is processing them.