Our back-end Exchange server 2003 recently began to report error eventID 9667 from time to time. I found related Microsoft articles explaining named properties and how to increase the quota limit. http://support.microsoft.com/kb/820379 But does anyone know how easily to determine the root cause other than performance tracking or calling MS? Most error entries are triggered by Blackberry service account though. As several users pointed out, increasing limit without knowing the root cause is not a best solution. Thanks for any help.

Your answer is there in link which you provided. Understanding the Impact of Named Property and Replica Identifier Limits on Exchange Databases The root cause of this is here, The MicrosoftExchange Information Store service maintains a table of named properties for each database. When it processes a message with custom information, it automatically adds an entry to the named properties table for any custom property that has not been previously processed. For example, when a company implements a new application that integrates with Exchangeand uses a specific Simple Mail Transfer Protocol (SMTP) X-header, the MicrosoftExchangeInformation Store service creates a named property for that custom information when it processes the first message that contains that information. Any subsequent messages that include the same SMTP X-header do not result in the creation of additional named properties. Here in your case Blackberry Application is using custom property that information store service is adding into named property butquota is reached its limit and giving 9667 error, ultimately you need to increase the named properties quota.

Thanks, Amit. I understand to increase the limit seems to be my only option at the moment to work around the error. However is there any way to prevent from reaching the limit in the first place? Or is that something it will eventually happen with applications and user activities? Then would it be a very silly design when the hard limit (32677) is reached and we have to move all the mailboxes out of that Exchange database? Is that how you read this MS article? Thanks very much. I appreciate your help.