As far as I know the "Software\Microsoft\Windows Messaging Subsystem" directory only appears under the HKEY_LOCAL_MACHINE area.

>Thanks Mike,
>
>But how do I know which main key to look under - HKEY_LOCAL_MACHINE or HKEY_CURRENT_USER ?
>
>Vidar
>
>>The following will give you a cursor that show all the messaging protocols registered on the client's system. If it is simple MAPI you want to use, loook for the entry under 'MAPI' (It should have a 1 for value). If it is extended MAPI look for MAPIX. If it is CMC look for it under CMC, if it is CDO look for the entry Ole Messaging.
>>

#Define ERROR_SUCCESS               0
>>#Define KEY_READ               131097
>>#Define KEY_ALL_ACCESS         983103
>>#Define HKEY_LOCAL_MACHINE     2147483650 && 0x80000002
>>Declare Integer RegCloseKey In advapi32 Integer hKey
>>Declare Integer RegOpenKeyEx In advapi32;
>>           INTEGER   hKey,;
>>           STRING    lpSubKey,;
>>           INTEGER   ulOptions,;
>>           INTEGER   samDesired,;
>>           INTEGER @ phkResult
>>Declare Integer RegEnumValue In advapi32;
>>           INTEGER   hKey,;
>>           INTEGER   dwIndex,;
>>           STRING  @ lpValueName,;
>>           INTEGER @ lpcValueName,;
>>           INTEGER   lpReserved,;
>>           INTEGER @ lpType,;
>>           STRING  @ lpData,;
>>           INTEGER @ lpcbData
>>hBaseKey = 0
>>lcBaseKey = "Software\Microsoft\Windows Messaging Subsystem"
>>If RegOpenKeyEx (HKEY_LOCAL_MACHINE, lcBaseKey,;
>>                       0, KEY_ALL_ACCESS, @hBaseKey) <> ERROR_SUCCESS
>>           ? "Error opening registry key"
>>Return
>>Endif
>>Create Cursor cs (valuename C(50), valuevalue C(200))
>>dwIndex = 0
>>Do While .T.
>>            lnValueLen = 250
>>            lcValueName = Repli(Chr(0), lnValueLen)
>>                       lnType = 0
>>            lnDataLen = 250
>>                       lcData = Repli(Chr(0), lnDataLen)
>>            lnResult = RegEnumValue (hBaseKey, dwIndex,;
>>                       @lcValueName, @lnValueLen, 0,;
>>                       @lnType, @lcData, @lnDataLen)
>>                       if lnResult <> ERROR_SUCCESS
>>                       Exit
>>           Endif
>>           lcValueName = Left (lcValueName, lnValueLen)
>>           lcData = Left (lcData, lnDataLen-1)
>>           Insert Into cs Values (lcValueName, lcData)
>>           dwIndex = dwIndex + 1
>>Enddo
>>=RegCloseKey (hBaseKey)
>>Select cs
>>Index On valuename Tag valuename
>>Go Top
>>Browse Normal Nowait

>>
>>Note that portions of this code comes from www.news2news.com
>>
>>
>>
>>
>>
>>
>>>>You have to find out if the other mail programs can and have established themselves as the Simple MAPI client or not. Outlook and OutlookExpress both have that as a configuration item under Tools/Options.
>>>
>>>Can't seem to find this option under Tools/Options in Outlook 2000. Do you know where it can be found there?
>>>
>>>Will setting this option (in Outlook or OutlookExpress) create the MAPI Profiles key (Software\Microsoft\Windows Messaging Subsystem\Profiles) in the registry if it doesn't already exist?
>>>
>>>Also, will the the MAPI Profiles key differ under different versions of Windows? (Please specify which key under which version.)