Which registry keys determine the Outlook Profile

This has changed in Outlook 2013:

• What's new for Outlook 2013 developers – Coexistence with previous Outlook versions

Profiles are stored under keys:

HKEY_CURRENT_USER\Software\Microsoft\Office\<version>\Outlook\Profiles

Where <version> is one of the following:

• Office 97 – 7.0
• Office 98 – 8.0
• Office 2000 – 9.0
• Office XP – 10.0
• Office 2003 – 11.0
• Office 2007 – 12.0
• Office 2010 – 14.0 (sic!)
• Office 2013 – 15.0
• Office 2016 – 16.0

The above version info was copied from this answer.

HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows Messaging Subsystem\Profiles\OutlookHKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows Messaging Subsystem\Simple MAPI-CMC

Firstly, for Outlook 97-2010 the profiles are stored in HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows Messaging Subsystem\Profiles.

Starting with Outlook 2013 (which supports side-by-side installations), the profiles are stored in HKEY_CURRENT_USER\Software\Microsoft\Office\%version%\Outlook\Profiles, where %version% is 15.0 for Outlook 2013, 16.0 for Outlook 2016, etc.

On the low (Extended MAPI) level, RPC-over-HTTP (ROH) settings are determined by the ROHFLAGS_USE_ROH bit in the PR_PROFILE_RPC_PROXY_SERVER_FLAGS property (0x66230003). That property is set in the global profile section as well as the particular Exchange store profile section (since Outlook now supports multiple Exchange accounts in a single profile).

You can see the data in OutlookSpy - click IMAPISession button on the OutlookSpy ribbon, click OpenProfileSession, select the {C8B0DB13-05AA-1A10-9BB0-00AA002FC45A} pbGlobalProfileSectionGuid entry from the combo box.

Note that Extended MAPI cannot be used from VB (or .Net). If using Redemption/Profman is an option, you can use the following script to enumerate all profiles and check if ROH is used:

  PR_PROFILE_RPC_PROXY_SERVER_FLAGS  = &H66230003  ROHFLAGS_USE_ROH = 1  set Profiles=CreateObject("ProfMan.Profiles")  for i = 1 to Profiles.Count    set Profile = Profiles.Item(i)    set GlobalProfSect = Profile.GlobalProfSect    Debug.Print "Profile: " & Profile.Name & " ------"    flags = GlobalProfSect.Item(PR_PROFILE_RPC_PROXY_SERVER_FLAGS)    If TypeName(flags) = "Long" Then      if (flags And ROHFLAGS_USE_ROH) = ROHFLAGS_USE_ROH Then        Debug.Print "   ROH is used"      Else        Debug.Print "   ROH is not used"      End If    Else      Debug.Print "   No PR_PROFILE_RPC_PROXY_SERVER_FLAGS"    End If  next

If you are already running Outlook and want to check that the current profile uses ROH, you can use RDOSession.ExchangeConnectionProperties.UseROH property:

set Session = CreateObject("Redemption.RDOSession")Session.MAPIOBJECT = Application.Session.MAPIOBJECTMsgBox Session.ExchangeConnectionProperties.UseROH