I've been working with Exchange 2010 up until 3 days ago. I accepted a new job which is running Exchange 2007, and earlier today, I noticed one of the mailbox server was flooded with the following event: Failed to create a new named property for database "First Storage Group/Mailbox" because the number of named properties reached the quota limit 8192. User attempting to create the named property: Our_HT_AND_CAS_SERVER I tried looking up the error code and although I did find the technet article and multiple article/blogs about it, I can't quite seem to wrap my head around it. I was hoping someone could clear this up for me. I understand that Exchange 2007 has a hard-coded limit of name properties, but what exactly are "named properties" and what do they store? What did Exchange 2010 do to fix this problem? I also read that X-Headers are stored as named properties, but I'm not quite sure what X-Headers are and what they're used for. Now, the big question, how do I correct this? So far, the solutions seems to be to increase the quota to 16k, or to create new mailbox databases and move the mailboxes to the new one.

MS Exchange team has the most comprehensive doc regarding named props, including the solution. If you have any further questions after reading please post again. Named Properties, X-Headers, and You http://blogs.technet.com/b/exchange/archive/2009/04/06/3407221.aspx Confused About Named Properties Quotas in Exchange 2003 and Exchange 2007? Join the Club! http://blogs.technet.com/b/exchange/archive/2010/07/29/3410545.aspxJames Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

http://blogs.technet.com/b/exchange/archive/2009/04/06/3407221.aspx http://blogs.technet.com/b/exchange/archive/2009/06/12/named-properties-round-2-what-lies-ahead.aspxEd Crowley MVP "There are seldom good technological solutions to behavioral problems."

Thanks for the quick response. I've read those articles, and I'm still a bit confused. I know how to correct the issue: upgrade to SP2, create new databases, or to strip X-Headers from anonymous users. What I don't understand is the concept of named properties. I've been doing some reading on X-Headers and from what I understand, X-Headers are basically custom header created to give additional information to the receiving mail server and could be created by just about anyone. If Exchange receives an email with an X-Header that's not already in the Named Properties table, it will add it in there. The part I dont understand is why it adds it in there? What purpose does that serve and how does Exchange benefits from storing the X-Headers? Name Properties, on the other hand, I'm still completely lost on. Summarizing the above articles: MAPI represent everything as a property, and assigned each property a PropID to distinguished one property from another. The value of these PropID range from 1 to "nearly unreachable". However, anything below 32,768 can be assigned to the server by any MAPI application. Ok, that sounds good...but what exactly are these "properties" and how are they used? I read that Outlook make extensive use of named properties but I don't understand what that means. Is a property a message, a setting, protocol information? I also read that every mail item have some MAPI properties, but again, no one explains what these properties actually are. If the above paragraph wasn't clear, let me see if I can put this in a development/programming context. If I created .NET object called objCar and told a fellow programmer to use it. He's going to ask me what properties my object have and I would tell him that it has a color property, a year, make, and model property. That's what I'm looking for. I understand that this Named Properties table is used to store MAPI properties, but I also want to know what these properties and their values are, rather than just "MAPI properties". Arg...thank goodness we're moving to Exchange 2010 soon.

Let's just say that it wasn't the best design decision on the part of the Exchange Team. They've recognized that and have given you a fix, even if it is a bit difficult to implement.Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."

Hi pham0329, Question1: Why X-Header that’s not already in the Named Properties table, it will add it there. In Exchange 2007, there are also some scenarios that still consume named properties to preserve X-Headers. You can know more detail from this document: Understanding the Impact of Named Property and Replica Identifier Limits on Exchange Databases(Scenarios that still consume named properties to preserve X-Headers section) http://technet.microsoft.com/en-us/library/bb851492(EXCHG.80).aspx Question 2: what exactly are these "properties" and how are they used? Named properties are made up of the following two main types: Properties that have numbers for names. These are properties that programs such as Microsoft Outlook use. These property names are generally defined in a source file. Properties that have string values for names. These properties are known as "String Named Properties." In addition to a name, each of these properties has an associated GUID. This allows developers to divide named properties into property sets. Thanks, EvanPlease remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.