Open .mai file in Outlook without renaming to .eml

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scotty562
Posts: 19
Joined: Tue Sep 11, 2018 12:20 pm

Open .mai file in Outlook without renaming to .eml

Post by scotty562 » Fri Sep 14, 2018 8:01 pm

When I try and open .mai files with Outlook I get "The command line argument is not valid. Verify the switch you are using." Is there a way to open these files with Outlook? Renaming them to .eml does work, but is inconvenient.

Admin
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Re: Open .mai file in Outlook without renaming to .eml

Post by Admin » Mon Sep 17, 2018 6:41 am

Hi,

You'll need to make sure you add /eml to the command being executed. So the command in your Windows registry should be something like:

C:\Program Files\Microsoft Office\Root\Office16\OUTLOOK.EXE /eml "%1"

The /eml is needed to tell Outlook what to open it as.

scotty562
Posts: 19
Joined: Tue Sep 11, 2018 12:20 pm

Re: Open .mai file in Outlook without renaming to .eml

Post by scotty562 » Mon Sep 17, 2018 4:13 pm

Would you mind exporting the registry key and uploading it as a .txt file attachment?

scotty562
Posts: 19
Joined: Tue Sep 11, 2018 12:20 pm

Re: Open .mai file in Outlook without renaming to .eml

Post by scotty562 » Mon Sep 17, 2018 5:00 pm

Ok I got it figured out. Here is the key that seems to have done it. If you get access denied when changing Progid check the permissions on the UserChoice key. There might be a deny flag set which you can unset (I would set it back when you are done). The Progid just needs changed to eml which already has the /eml set. Is there a reason this isn't done during install? It seems like it would solve many headaches.


Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.MAI\UserChoice]
"Progid"="Outlook.File.eml.14"

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