A single MAPI session has exceeded the maximum number of objects of a given type.

Well we all have users with ENORMOUS mailboxes - even though there are no practical limits on mailbox size we all know that there are many more variables that influence the "actual" performance of email access (lan speeds, PC age, Exchange server sizing, etc)

We came across this at a few sites and the following helped us get around it.

Description:
This is caused by a very high usage level by an individual user. If these errors are happening regularly, you can raise the default maximum for the affected object type (for example, to twice its default level). If at this level the specified user is continuing to generate this warning, investigate the user actions that are causing this warning. It can be caused by improper client design or unusual client usage patterns.


Resolution for Exchange 2007

To resolve the problem, do the following:

•Investigate any third-party applications or add-ins that are running on the MAPI client. Some third-party applications keep objects open for long periods of time or open many objects concurrently.
(Blackberry server, Virus Scanners for Email Servers -- always run a separate gateway not on SERVER!!!)
•Investigate the user behavior that is associated with the indicated logon. This will help you better understand why the default number of objects is insufficient.

•In rare cases, you may need to add a registry key to adjust the maximum number of open objects. This new registry key will override the default value. Such rare cases include situations in which it is acceptable or necessary to use applications that keep objects open or open many objects concurrently.

Caution:
When you increase the maximum number of an object type, you also increase the memory that may be consumed by all client requests connecting to the server. Incorrectly configuring this value could lead to out-of-memory warnings or virtual memory fragmentation warnings.

Caution:
Incorrectly editing the registry can cause serious problems that may require you to reinstall your operating system. Problems resulting from editing the registry incorrectly may not be able to be resolved. Before editing the registry, back up any valuable data.

Before You Begin
To perform the following procedure, the account you use must be delegated membership in the local Administrators group. For more information about permissions, delegating roles, and the rights that are required to administer Exchange 2007, see Permission Considerations.
Procedure

To use Registry Editor to adjust the maximum number of open objects that a MAPI client can use at the same time

1.Start Registry Editor (regedit).
2.Locate the following registry subkey: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\ParametersSystem
3.Right-click ParametersSystem, point to New, and then click Key.
4.Type MaxObjsPerMapiSession, and then press ENTER to name the new subkey.
5.Right-click MaxObjsPerMapiSession, click New, and then click DWORD Value.
6.Type the object type, and then press ENTER to name the entry. For example, type objtMessage, and then press ENTER to create an entry that changes the default maximum of objtMessage objects.
7.Right-click the entry that you created in Step 6, and then click Modify.
8.In the Value data box, type the new maximum number of objects to which you want to limit this entry, and then click OK.

Note:
The server will automatically recognize the new limit within five minutes.

Exchange Server Version??

When you look at the properties of an Exchange server you see the version number specifed as... 8.1.0240.006, etc..  To match the numeric build of Exchange to the actual version refer to the link below for the matching matrix.

Microsoft Exchange Server 2007 8.0.685.24 or 8.0.685.25
December 2006

Microsoft Exchange Server 2007 SP1 8.1.0240.006
November 2007

Microsoft Exchange Server 2007 SP2 8.2.0176.002
August 2009

Microsoft Exchange Server 2007 SP3 8.3.0083.006
June 2010

Microsoft Exchange Server 2010 14.00.0639.021
October 2009

Microsoft Exchange Server 2010 SP1 14.01.0218.015
August 2010



Build numbers and release dates for Exchange Server
Article ID: 158530
http://support.microsoft.com/kb/158530

Active Directory Schema Update Versioning

Ever wonder if a schema update applied properly or what version you are currently using?
Well these handy dsquery commands will make it easier:

For Active Directory Schema version

"dsquery * cn=schema,cn=configuration,dc=<< your domainname here>>,dc=local -scope base -attr objectVersion"

For Exchange Schema version

"dsquery * CN=ms-Exch-Schema-Version-Pt,cn=schema,cn=configuration,dc=<>,dc=local -scope base -attr rangeUpper"

Reference the results for the above dsquery commandlets to the following lists below:


Schema version for operating system

13 - Windows 2000 Server
30 - Windows Server 2003 RTM, Windows 2003 With Service Pack 1, Windows 2003 With Service Pack 2
31 -Windows Server 2003 R2
44 - Windows Server 2008 RTM
47 - Windows Server 2008 R2

Schema version for Exchange application
4397 -Exchange Server 2000 RTM
4406 -Exchange Server 2000 With Service Pack 3
6870 -Exchange Server 2003 RTM
6936 - Exchange Server 2003 With Service Pack 3
10628 - Exchange Server 2007
11116 - Exchange 2007 With Service Pack 1
14726 - Exchange 2010 With Service Pack 1

The source server is currently rejecting replication requests

I got this error while troubleshooting an environment with two DC’s that were not replicating. This error popped up when I tried to manually replicate in AD sites and services.

I used the repadmin tool to troubleshoot and found that the server had replication turned off.

Repadmin /option *servername* -- this will show you what the current settings are for the DC in question.

Enabling replication resolved the issue, here is the syntax

Use both:

repadmin /options *servername* -disable_inbound_repl

repadmin /options *servername* -disable_outbound_repl