Mapi profile corrupted after Adding domain on Microsoft 365
Question asked by Matteo - 9/29/2022 at 1:58 AM
my customer registered the domain on microsoft 365, and the Outlook clients configured in Mapi stopped working.
If I try to create a new profile automatically it asks me to access with the Microsoft 365 account.

But the old profiles are corrupt, is it not possible to restore them somehow? I have many PCs to reconfigure


4 Replies

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This is a BUG (or maybe a feature requested by Microsoft?) in Outlook - if you register your domain on Microsoft 365, Outlook Autodiscover for MAPI ALWAYS tries to connect to Microsoft 365 and won't connect to other services.

You can avoid this with a mod in the Windows registry that tells Outlook NOT to use Microsoft 365 with the Autodiscover service.

At the moment I don't have a tutorial to do it, I will post it later if I can (but you can find it by searching the community ...)

Gabriele Maoret - SERSIS - Head of SysAdmins
Currently manages 3 SmarterMail installations (1 in cloud for SERSIS which provides service to a few hundreds 3rd party Mail Domains + 2 on premise to customers)
Kyle Kerst Replied
Employee Post
Hey Matteo, sorry to hear you're having trouble with this, and I hope we can save you some time here! I believe you may be able to get those existing profiles open with a couple of modifications to those client PCs beforehand. First, you'll want to implement the registry key change outlined here:

That tells Outlook to prefer the XML it gets back from SmarterMail. Next, you can add an entry like the one below to the client PC's C:\Windows\System32\Drivers\etc\hosts file:        outlook.office365.com
Once you get that added to the file, save it to the desktop (it won't let you save directly to that path) then copy the replacement (with no file extension) in to replace the original. Finally, give the PC a reboot to force the changes into place. That change will tell the PC to redirect calls to outlook.office365.com back to the local results it got from SmarterMail. Can you give this a shot and let us know if it helps?
Kyle Kerst
Technical Support Specialist
SmarterTools Inc.
(877) 357-6278
Tim Uzzanti Replied
Employee Post Marked As Answer
Appreciate Kyle chiming in!

Microsoft is doing a VERY poor job cleaning up Office365 data which is intentional and to their benefit.   It is forcing people to make configuration changes, like what Kyle provided.

In addition, Microsoft is also introducing man in the middle servers that all your email will flow through on its way to Microsoft Outlook (so they have access to everything), even if you don't use Microsoft mail servers.  

Microsoft is giving users a lot of reasons NOT to use Microsoft Outlook and why SmarterTools is working very close with a number of companies who make email clients.

More information to come!
Tim Uzzanti
SmarterTools Inc.
(877) 357-6278
Stefano Replied
That's the commands that I usually run

reg add HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\AutoDiscover /t REG_DWORD /v PreferLocalXML /d 1
reg add HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\AutoDiscover /t REG_DWORD /v ExcludeExplicitO365Endpoint /d 1

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