Hello All, Please help me... I have experienced the following issue MaxConcurrentMailboxSubmissions Event ID 1009 Could someone please tell me if I need to increase the MaxConcurrentMailboxSubmissions from the default of 20 if I have dual quad core processors in my hub/cas server and my mbx cluster. The following ms tech not mentions the following: http://technet.microsoft.com/en-us/library/bb217599(EXCHG.80).aspx "This Warning event indicates that there are too many RPC mail submission threads on this Exchange server. This warning may indicate that you should modify settings on the server. The maximum number of threads that the Microsoft Exchange Transport Service can use for submissions are as defined by the MaxConcurrentMailboxSubmissions attribute. The default is 20, multiplied by the number of processors on the server." I would welcome any help from MSFT if poss Many Thanks Paul

I believe an increase would make things worse not better. Note it says "20 x dual quad core" and the message you are getting is that you have too many so increasing it would make even more.I would think maybe reducing it would be the thing to do but first question is probably what is the performance of the server at the moment?

If that is the case, then Exchange 2007 has dynamic settings and changes to match the hardware. I thought this was a manual change? I am still confused...sorry !!?