I receive this error message when I try do changes on events by Outlook 365 on Windows 10.

Question

When I try to change events with Outlook 365 on Windows 10. I received this error message. Other hand I can make any changes to this event using Outlook 365 on the web. When I make changes on the web, I can see these changes on my Outlook 365 on Windows 10. This event is presented on the Exchange Online server.

If I disable Microsoft Exchange Add-in on my local Outlook, I can make any changes using my Outlook 365 on Windows 10.

P.S. I use (Microsoft® Outlook® for Microsoft 365 MSO (Version 2311 Build 16.0.17029.20108) 32-bit)

Answer 1

Hello Vladislav Shihov,

Good day! Thank for your reply and sharing more information!

Firstly, I am glad to know that you find the temp workaround to fix this case to modify these two series of events finally. To clarify this case, Microsoft Exchange add-in supports for Unified Messaging, e-mail permission rules, and calendar availability. If there is something wrong with Microsoft Exchange add-inin Outlook, it may cause the issue for calendar availability which may affect some series of events in Outlook for Windows. This may be the reason why you could make changes again for these two series of events after disabled Microsoft Exchange add-in.

Thus the file of Microsoft Exchange Add-in is UmOutlookAddin.dll which is under C drive as above Location. If damaged or not working well, you may need to fix this file or try to re-load this add-in from C drive with the same path again. The better solution is that you may have to repair your Office application or re-install Office application finally. Hope you my workaround is helpful, if there is any other concerns, please also let me know.

Again, your understanding and patience will be appreciated.

Thank you!

Answer 2

Hello Vladislav Shihov,

Thank you for posting this case in Microsoft Community!

Based your description: You received this error message when you tried to do changes on events in Outlook for Windows. I would like to cooperate with you working on this case. For my suggestion, you may check following workaround:

1. Firstly, please try to do changes on any other events as well in Outlook client. You need to make sure if this case only happened on this specific event or all events. You may also restart your Outlook client as well as Windows system.
2. If this case happened on all events, you may check this Microsoft article as reference to fix the issue.

The operation failed error when you send email messages in Outlook

3. Then you go to Search menu and type Outlook.exe / safeto open Outlook client to test it again.

4. You may also try to re-configure new Outlook profile and test it if working or not. Create an Outlook profile - Microsoft Support
5. Then you may try to repair your Office 365 application and test if working or not.

Steps:

**A.**Quit any Microsoft 365 programs that are running.

B. In Control Panel, choose Programs and Features.

C. In the list of installed programs, right-click Microsoft Office 2016 or Microsoft Office 2013, and then choose Change.

6. Next you may run SARA Tool to fix this case if possible. About the Microsoft Support and Recovery Assistant

7. If this case still persists, finally, you may try to re-install the latest version of Office 365 application and check if working or not.

Download and install or reinstall Microsoft 365 or Office 2021 on a PC or Mac - Microsoft Support

If you need further assistance, please feel free to let me know, I will keep assisting you.

Your understanding and patience will be appreciated.

Thank you!

Thx for your reply.

1. I have a problem with just for two series of events. Rest of the events on my SharedMailbox calendar I can change normally.
2. The problem just for a calendar for SharedMailbox is not my case.
3. I wrote "IF I DISABLE MICROSFOT EXCHANGE ADD-IN" I can make any changes for my problematic events.
4. I made a new profile, and I've added access to different users. I HAVE THE SAME PROBLEM
5. I have just installed Office 365 for enterprise (no Office 2013 or any Offices)
6. The SARA Tool does not sense to me. I have a problem with just for two events. My Outlook can see changes if I make it by WEB Outllok.

Any ideas?

My question is "WHY WHEN I DISABLE MICROSOFT EXCHANGE ADD-IN I CAN MAKE CHENGES TO THIS EVENTS?"

Thx.

Answer 3

Hello Vladislav Shihov,

Thank you for posting this case in Microsoft Community!

Based your description: You received this error message when you tried to do changes on events in Outlook for Windows. I would like to cooperate with you working on this case. For my suggestion, you may check following workaround:

1. Firstly, please try to do changes on any other events as well in Outlook client. You need to make sure if this case only happened on this specific event or all events. You may also restart your Outlook client as well as Windows system.
2. If this case happened on all events, you may check this Microsoft article as reference to fix the issue.

The operation failed error when you send email messages in Outlook

3. Then you go to Search menu and type Outlook.exe / safeto open Outlook client to test it again.

4. You may also try to re-configure new Outlook profile and test it if working or not. Create an Outlook profile - Microsoft Support
5. Then you may try to repair your Office 365 application and test if working or not.

Steps:

**A.**Quit any Microsoft 365 programs that are running.

B. In Control Panel, choose Programs and Features.

C. In the list of installed programs, right-click Microsoft Office 2016 or Microsoft Office 2013, and then choose Change.

6. Next you may run SARA Tool to fix this case if possible. About the Microsoft Support and Recovery Assistant

7. If this case still persists, finally, you may try to re-install the latest version of Office 365 application and check if working or not.

Download and install or reinstall Microsoft 365 or Office 2021 on a PC or Mac - Microsoft Support

If you need further assistance, please feel free to let me know, I will keep assisting you.

Your understanding and patience will be appreciated.

Thank you!

Answer 4

Dear 

Thank you for posting to Microsoft Community. We are happy to assist you.

We are looking into your situation, we will update the thread shortly.

Appreciate your patience and understanding and thank you for your time and cooperation.

Sincerely,

Kerry | Microsoft Community Moderator