Hi,We just received problem with the maximum numbers of MAPI sessions. The user that gets this problem is an migration user that open numerous of IMAP sessions. But i Guess as it's 2010 this converts to MAPI sessions from the CAS to the MBX... We think this came with rollup 1 but even an uninstall of rollup 1 did not solve the issue. This has worked fine before..We have tried the 2003/2007 reg keys for highering the values with the MaxObjsPerMapiSession keys and the Maximum Allowed Sessions Per User key. http://support.microsoft.com/default.aspx?scid=kb;EN-US;842022http://support.microsoft.com/kb/830829We also tried the View information store status permission but nothing helps...How does you increase the number of mapi sessions in 2010?? Any help is appreciated..... Al old articles for 2003 AND 2007 seems to have an default value of 32. but the error here says 16??Log Name: ApplicationSource: MSExchangeISDate: 2010-01-18 14:54:22Event ID: 9646Task Category: GeneralLevel: ErrorKeywords: ClassicUser: N/AComputer: XXXXXDescription:Mapi session "/o=XXXX/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=GU MIG" exceeded the maximum of 16 objects of type "session".Event Xml:<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event"> <System> <Provider Name="MSExchangeIS" /> <EventID Qualifiers="49158">9646</EventID> <Level>2</Level> <Task>6</Task> <Keywords>0x80000000000000</Keywords> <TimeCreated SystemTime="2010-01-18T13:54:22.000000000Z" /> <EventRecordID>370761</EventRecordID> <Channel>Application</Channel> <Computer>XXXXX</Computer> <Security /> </System> <EventData> <Data>/o=XXXX/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=GU MIG</Data> <Data>16</Data> <Data>session</Data> <Binary>080000005B444941475F4354585D000016000000FF381500000000000002080000003A67F01FFE000000</Binary> </EventData></Event>

Hi Carl,Create store.exe.config file in folder C:\Program Files\Microsoft\Exchange Server\V14\Binwith content<?xml version="1.0" encoding="utf-8" ?><configuration> <runtime> <gcServer enabled="true" /> <generatePublisherEvidence enabled="false"/> </runtime> <appSettings> <!-- Specifies the maximum number of sessions permitted per user. --> <add key="MaxSessionsPerUser" value="5000" /> </appSettings></configuration>Restart MSexchangeIS service and tryBest regards,Vitaliy

Tried to create the config file but it did not work..... Even tried to do a complete reboot but with no luck. Also tried to lower the value to 32 but still the error says 16.....

Did you get this to work???

Before make it on my exchange I got error with 32 objects.After make it I can now make changes for few hundred public folders in one command (Add-PublicFolderClientPermission)Rollup 1 has installed on my server.try to add in microsoft.exchange.addressbook.service.exe.config <!-- Specifies the maximum number of sessions permitted per user. --> <add key="MaxSessionsPerUser" value="5000" />I have only changes in those files.The 2003/2007 reg keys for highering the values with the MaxObjsPerMapiSession keys and the Maximum Allowed Sessions Per User key not help me too.

it can't be that value in the addressbook.service.exe.config as that value is currently set to 50 and we get warnings at 16....

<!-- Specifies the maximum number of sessions permitted per user. --> <add key="MaxSessionsPerUser" value="50" /> </appSettings>

Check file "C:\Program Files\Microsoft\Exchange Server\V14\ClientAccess\PopImap\Microsoft.Exchange.Imap4.exe.config"

Hi All, For me, it was the solution to create these registry keys: HKLM\SYSTEM\Current Control Session\Services\MSExchangeIS\ParameterSystem\MaxObjsPerMAPISession ObjtFolder, ObjtMessage, ObjtFolderview, both are DWORD, and I set it to at least 700, then restart the Information store service. Then the Event ID 9646 error messages disappeared. Best, Tamas