My exchange server is logging event ID 9667. Here is the error message: Failed to create a new named property for database "First Storage Group\Mailbox Database" because the number of named properties reached the quota limit (8192). User attempting to create the named property: "NETWORK SERVICE" Named property GUID: 00020386-0000-0000-c000-000000000046 Named property name/id: "x-nap.edu-mailscanner-watermark" For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.I have researched this on the web and found the following articles on the subject from Microsoft.http://technet.microsoft.com/en-us/library/bb851495.aspxhttp://technet.microsoft.com/en-us/library/bb851492.aspxhttp://technet.microsoft.com/en-us/library/bb851493.aspxIt seems that there really is no fix for this. You can enlarge the quota which will delay theproblemfor awhileor strip off the x-headers with a third party applicationbut neither solutions really solves the problem.Since this seems to be mail coming in I don't see how we can stop these from coming in. If I ignore this message will if affect my mail flow and in what ways will it affect the mail flow? What is the best solution to this?

Hi, I recommend you to move mailbox to a new store. Besides, Id like to share with you some explanations of Named properties.1. Using Named properties to store values that only pertain to them. The definition of this properties are stored in the named props table.2. The second use of the named props table is related to incoming SMTP messages. When mail arrives from the internet, it can contain any number of customer X- headers and their associated value. The headers must be preserved in some fashion. When a message is fully converted from MIME to MAPI format, we must save these X- headers off somewhere inside the EDB file. Each unique X- header encountered becomes a separate entry in the named props table. For example if the following headers were encountered they would become 2 unique entries in the named props table. If they are encountered again in a later message, no big deal, we already have a definition for them.Regards,Xiu

Supplement:Not sure which version of Exchange do you have?In Exchange 2007, you can place a transport agent HeaderFilterAgent on Hub or Edge transport server to strip out x-headers coming in,except mentioned in white list but this applies only on the emails which are received from internet and internal Exchange mailflow remains intact.Download and instructions: http://www.codeplex.com/HeaderFilterAgentAmit Tank | MVP - Exchange | MCITP:EMA MCSA:M | http://ExchangeShare.WordPress.com

What happens if the mailbox in the error is SYSTEM, what can be done?