We are approaching the quota for the number of non-MAPI named properties. I found this article - http://technet.microsoft.com/en-us/library/bb851493.aspx which explains how the quota can be increased.However, I was a little uncertain about the maximum hard limit for the properties. Is the maximum value 32767 for each type, i.e. 32767 named properties, 32767 non-MAPI named properties and 32767 replica identifiers. Or is the combined limited capped at 32767 as this article seems to suggest: http://technet.microsoft.com/en-us/library/bb851492.aspxI'm hoping someone can clarify this, thanks.

Yes, the max value for each type is 32767 By default: Named Properties Quota 16K (16,384) Non-MAPI Named Properties Quota 8K (8,192) Replica Identifiers Quota 8K (8,192) Do not increase the quotas to the hard limit of 32,766 entries. If you must increase the default quota for either named properties or replica identifiers, you should identify the root cause for the situation and not allow the named properties or replica identifiers to reach the maximum limit. ------------------<Named Properties or Replica Identifiers Are Depleted for An Exchange Database> Another workaround besides increase the quota is, to distribute the fewer mailboxes per database, so the warning or error would take more time to occur However, the best method to eliminate the quote warning and error events is, dump the named Properties table from Information Store to check the properties. Figure out which application they are coming from and get that changed. Please review Dgoldmans post in this thread

Which version of Exchange do you use?Addition to James' reply, you can implementa transport agent in Exchange 2007 which strips all X- headers from incoming internet emailexcept listed headers in whitelist registry.This really helps a lot toprotect named prop table from random X- headers of internet emails.HeaderFilterAgent for Exchange 2007http://www.codeplex.com/HeaderFilterAgentAmit Tank | MVP - Exchange | MCITP:EMA MCSA:M | http://ExchangeShare.WordPress.com