Fix Outlook Error While Preparing to Send Sharing Message

Many users have reported that while attempting to send a calendar invite through Outlook they get the following error:

Error while preparing to send sharing message

Error While Preparing To Send Sharing Message

Where “sharing message” refers to the calendar invite.

This error usually occurs with Outlook 2007, 2010, and 2016. A noteworthy observation is that most users who reported the issue were able to send the email invite through the online app of the mailbox mappen on the Outlook desktop client.


The causes behind the issue are as follows:

1] The files responsible for acting a bridge between the Calendar app and Outlook might be damaged.

2] An add-in might be causing the issue.

3] Issue with Calendar permission files on the system.

4] The system time might be incorrect

Preliminary step

Before anything else, try sending the calendar invite through the web application (eg.,, etc.) of your email server. If it doesn’t work with the web application either, then there’s no point in troubleshooting with the system. You could contact your email service provider for the same.

Thereafter, proceed with the following solutions:

1] Check the system date and time

2] Use the Microsoft Support and Recovery Assistant for Office 365

3] Remove troublesome add-ins

4] Re-install Microsoft Office completely



Solution 1] Remove troublesome add-ins

At times some troublesome add-ins cause this issue. We could test this, and if the issue is with one of the add-ins, we could investigate and remove the same.

1] Press Win + R to open the Run window and type the command outlook.exe /safe. Press Enter to open the Outlook desktop app in Safe mode. When we open the Outlook desktop client in Safe mode, the add-ins would be disabled.

Open Outlook In Safe Mode


2] Now try sending the Calendar invite. If it works, the issue is with one of the add-ins.

3] Close the Outlook Safe mode window and open the Outlook client in normal mode.

4] Go to File >> Options >> Add-ins.

5] Choose the drop-down menu corresponding to Manage to COM Add-ins and click on Go.

6] Check and Remove any add-in that is suspicious. This would be more of a hit and trial activity.


Remove Problematic Add In Min


Solution 2 – Remove Previous Microsoft Office Login Credentials

1. Press Windows Key + R together to Open RUN command Box.

2. Now,  Write control /name Microsoft.CredentialManager  in the run command box and Click OK.


Microsoft Credential Manager Min


3. Now, Choose Windows Credentials.


Windows Credentialsd Min


4. Now, Expand Microsoft Office Credentials from the List and Remove it.


Remove Office Credentials Min


Solution 3- Remove Duplicate Entry

  • Right Click on the users calendar and select Properties.
  • Choose permission tab.
  • Go to  users list and make sure that there aren’t any duplicate entry.
  • If there is any Duplicate entry , Remove it.
  • Once you remove the Duplicate Entry , Just restart Outlook again.


Solution 4] Use the Microsoft Support and Recovery Assistant for Office 365

The Microsoft Support and Recovery Assistant for Office 365 can be downloaded from here. Run this troubleshooter for the Outlook desktop client. It check for all possible causes of the issue and tries to resolve it if possible.

Solution 5] Re-install Microsoft Office completely

If everything else fails, you could consider re-installing the Microsoft Office package. However,it is necessary to remove all components of the software package. To do so, download the tool mentioned in Option 2 here. Thereafter, reinstall the Microsoft Office package.

Solution 6] Check the system date and time

The Outlook client or rather any software installed on the system uses the system clock to check the time and use it for functions. Check the system time at the right-bottom corner of the screen. If it is wrong, you might have to correct it.

1] Search for Control Panel in the Windows search bar and open the same.

Search For Control Panelin The Windows Search Bar


2] Go to Date and Time and then to the Internet time tab.


Date And Time In Control Panel


3] Click on Change settings.

Internet Time Change Settings


4] Select the Server to and then click on Update now.


Choose Internet Time Server


5] Click on OK to save the settings.