It’s back again:

Source: MSExchangeIS
Error ID: 9646
Description: Mapi session “xxxx: /o=OrganizationName/
exceeded the maximum of 500 objects of type “objtFolder”.

Microsoft Exchange 2010 server logs the above message. While on the client end Outlook client doesn’t update folders automatically.

The number of server-side objects that are allowed by clients is limited to prevent a single client from the exhausting resources on the Exchange server.

To resolve this problem:

1. Open Registry Editor and navigate to:


2. Right click ParametersSystem and create New -> Key

3. Enter MaxObjsPerMapiSession and confirm creation of the new sub-key

4. Right click newly created key, create new DWORD value called objtFolder and give it a decimal value bigger than default 500.

5. Create another DWORD value called objtFolderView and give it the same value.