A. Outlook 2010 supports three Exchange server connections concurrently by default, but you can increase this limit to up to 15.
You can make the change through Group Policy or the registry. The Group Policy setting is located at Administrative Templates, Microsoft Outlook 2010, Account Settings, Exchange. Double-click Set maximum number of Exchange accounts per profile and set the required number of accounts. You need to import the ADMX files onto the machine editing the group policy object before the settings are available.
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To make this change in the registry, navigate to HKEY_CURRENT_USER\Software\Policies\Microsoft\Exchange and set the DWORD value MaxNumExchange to the new limit (between 1 and 15).Related Reading: