I've just noticed this event in my logs, and it looks pretty serious, but I can't find the KB article most people cite: 820379
I've found http://technet.microsoft.com/en-us/library/bb851495.aspx, but don't know just how concerned I should be. Text of the event is: The number of named properties created for database "First Storage Group\Mailbox Store (XCH)" is close to quota limit. Current number of named properties: 8190 Quota limit for named properties: 8192 User attempting to create the named property: "SYSTEM" Named property GUID: 00020386-0000-0000-c000-000000000046 Named property name/id: "X-MS-WT" ~ Ninja Email Security with Cloudmark Spam Engine Gets Image Spam ~ ~ http://www.sunbeltsoftware.com/Ninja ~