MAPI, Windows 10, replacing Outlook

I recently downloaded emClient as I am searching to replace Outlook.  I really like love the emClient interface and the speed.

The last thing that I seemed stumped on doing is replacing the default email client fully.  My main software uses Simple MAPI to send invoices out, but despite setting all of the program defaults to emClient (from Outlook), the Outlook still pops up when sending.

I really wish that I could uninstall Outlook 365, but it seems to be inseparable from Office 2013 and insists on lingering in the computer.  I know that I have the default MAPI client set to emClient but I am wondering if maybe the software that sends our invoices may be using XMAPI instead of Simple MAPI.  I am going to do some experimenting this weekend to tinker with the protocol, but was wondering if anybody else has had a similar issue.

By the way, if I use Windows Explorer and right click a file, and pick Send To, emClient comes up.

Windows version 10
Outlook 2013

Also using Kapersky Anti-Virus (if that matters)



Update:  The program that I use is one that we write.  We tried changing the SendMail protocol to each of SMAPI, MSMAPI, XMAPI and it would never try to send through emClient, but always either MS Mail or Outlook. 

I checked and double (and triple) checked the Default settings and there has been 0 success in getting emClient to popup as the email client on my Windows 10.  It seems that Office 2013 always wants to intercept the call.

Too bad, because I am otherwise liking what I see in emClient.


I found the answer and am posting it here for anybody who has the same issue.

My system is Windows 10 and I have been trying to get rid of Outlook simply because it is just plain awful.  I have tried a few different email clients but could never get one of my programs (which happens to be 16 bit) open up the eM Client… it would always open up Outlook.

Here is the solution:
When you change the Windows default email client, it makes a change to the following registry key:
HKEY_LOCAL_MACHINE\Software\Clients\Mail::(default) registry value
where it names the default client

BUT it doesn’t change this key:
HKEY_LOCAL_MACHINE\Software\WOW6432Node\Clients\Mail::(default) registry value

When I manually change it, then my 16 bit program then connects to my default email Client.


Hi Mike,
I was just at the point of attempting to replicate the issue, but thank you for finding and sharing the solution with us :slight_smile:

Best regards,

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