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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.
Update from In-App Support today. They are aware that this is an Outlook bug. No ETR given.
Hi all,
The Outlook Team has disabled a feature from the service that they suspect is causing the issue. It was just disabled two hours ago. Sometimes it can take up to five hours for Outlook to automatically pick up the change.
We are also not sure if the problem will stop automatically or not with the feature disabled. Outlook Dev says It might be necessary to create a new Outlook Profile to fully resolve it, Create an Outlook profile (microsoft.com). If you don't see it auto resolved by tomorrow, please create a new profile and let us know if it addresses the issue.
Thanks, Gabriel. No immediate change in behavior this morning, although I'll need to come back later to try deleting/recreating the profile when I have more time. My current Outlook version is 16.0.14931.20042 64-bit. I have in-app support case 1663610532 open, and they are asking me to collect some debug logs and run a PowerShell script to disable an Outlook feature that they think is related to the problem. I'll get to that this weekend and advise this thread of the results. Jeff.
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.
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.