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Using Microsoft Outlook version 2201 (Preview Channel) I get the same error on two different computers when I use Reply All:
The operation failed. The messaging interfaces have returned an unknown error. If the problem persists, restart Oulook.
I already tried to restart outlook, change profile, create another profile, but the error continues.
Creating a new profile I also created a new .OST file, so I would exclude that the issue is a corrupt file.
The error does not show when I am connected to a personal Hotmail account. The error only shows up on my work account.
Because it happens now on two different computers (desktop and notebook) it does not seem something corrupted at the PC level.
Additional note: also ReplyAll from VBA (using Outlook.MailItem) failed, in that case without showing the dialog box UI.
The Reply and Forward buttons and corresponding VBA commands work regularly.
I also monitored with Process Explorer to see whether there are errors accessing Registry or File System, but I didn't see any particular error when I click "Reply All".
In the Event Viewer I have this entry in the Microsoft Office Alerts:
Microsoft Outlook
The operation failed. The messaging interfaces have returned an unknown error. If the problem persists, restart Outlook.
P1: 301670
P2: 16.0.14827.20186
P3:
P4: 0x80004005
My only suspect at this point is that there is something that happens with version 2201, but I don't know how to get more details about the error to investigate deeper. Any help would be welcome.
Using Classic Outlook on Windows for personal email, calendar, and contact management
Locked Question. This question was migrated from the Microsoft Support Community. You can vote on whether it's helpful, but you can't add comments or replies or follow the question.
I have created a new profile after seeing this post and can confirm this issue has now been resolved.
Outlook in-app support has closed my case given that creating a new Outlook profile fixed the problem. I cleaned up by deleting both Outlook profiles and the C:\Users<profile>\AppData\Local\Microsoft\Outlook directory and starting over. All appears to be well at this point.
Gabriel, In their latest post, Outlook in-app support asked me to restart Outlook 5 times, and recheck, but that had no effect on the Reply All problem. Then they asked that I create a new Outlook profile. I did that, adding all three of the email accounts that I normally use, and that did fix the problem. Reply All works normally in the new profile, but continues to fail in the original one. I have the three email addresses of the three accounts in the profile in the From drop-down, for both the original and the new profile. Thanks. Jeff.
I have 10 aliases, but this does not seem a good solution because the problem depends on the device and something else, but it is not happening on all the devices: at the moment, only on one notebook and one desktop, not on another two notebooks.
Jeff,
Please skip the Powershell steps that In App provided. They were trying to test turning off the feature before actually turning it off from the service.
A root cause the Outlook Dev mentioned was he saw that the Outlook Profile key PR_PROFILE_USER_MANAGED_ALIASES_W somehow had too many aliases and Outlook was not handling that properly causing the error. I believe he said the limit was 30 aliases before it might cause issues. The theory is if you create a new Outlook profile that profile property will get reset back.
That PR_PROFILE_USER_MANAGED_ALIASES_W is supposed to map to what you see in the From drop down when you write an email. If you create a new email and click the From dropdown, do you have many aliases listed there? Were these aliases you added or created by Outlook? I know a lot of people use aliases for work e.g. sales, support, etc. Just curious why I am not causing a repro when I added a bunch of aliases to my account. There must be something more to it.