The Read status of email messages may not be updated between Exchange ActiveSync

Original KB number:   2804607

Problem

The Read status of email messages may not be updated between Exchange ActiveSync on a user's mobile device and the user's Microsoft Exchange Online mailbox in Microsoft 365.

Workaround

To work around this issue, re-create the user mailbox. To do this, follow these steps:

Step 1: Prepare to replace the existing mailbox

Export the contents of the existing mailbox to a .pst file for backup. To do this, follow these steps:

1. Ask the user to make sure that any items that were created on mobile devices or other mail clients are synchronized to the mailbox.

2. Export the whole contents of the mailbox to a .pst file for backup.

   Note

   This may require some time for larger mailboxes. The time that is required varies based on mailbox size, network conditions, and local computer performance.

3. In Microsoft Outlook, on the File menu, select Account Settings, and then select the Data Files tab. Select the backup .pst file, and then select Remove.

4. Exit all Outlook clients that access the user's mailbox.

Step 2: Rename the existing mailbox

To rename the existing mailbox, follow these steps:

1. Sign in to the Microsoft 365 portal (https://portal.office.com) as an administrator.

2. In the header, select Admin, and then, under Management in the left navigation pane, select Users.

3. In the list of users, select the user whose mailbox you want to re-create, and then select Details. In this example, the user name is John Smith.

4. In the Display name box, change the display name of the user, and then click Save. For example, change John Smith to John Smith2.

   Note

   Changing the user name in the portal also changes all other values for the user except the proxy email addresses.

5. Select More, and then select Change mailbox settings.

6. Expand E-Mail Options.

7. In the Other e-mail addresses box, delete or change the other email addresses as needed, and then select Save.

8. Select Save again to return to the Users page.

Step 3: Create a new mailbox

Create a new user account. This new user account replaces the existing user account. To do this, follow these steps:

1. In the header, select Admin, and then, under Management in the left navigation pane, select Users.

2. On the Users page of the Office 3365 portal, select New, select User, and then follow the instructions to create a new user account.

   For example, create a new user account that's named John Smith. This is considered a new user account because the original user account that was named John Smith was renamed to John Smith2 in step 2.

   Note

   You may receive an "A user with this name already exists. Use a different name" error message. If you do receive this error message, you have to wait for the changes that were made to the original account to replicate throughout the service before you can create the new user account. Also, make sure that the proxy addresses are updated, because you may receive this error message if there's a conflict with a proxy address.

Step 4: Assign permissions to the new mailbox

To assign permissions to the new mailbox, follow these steps:

1. Connect to Exchange Online by using remote PowerShell. For more information about how to do this, see Connect to Exchange Online PowerShell.

2. Assign the user Full Access permissions to the new mailbox. For example, to assign John Smith Full Access permissions to the John Smith2 mailbox, run the following command.

   Add-MailboxPermission -Identity "John Smith 2" -User "John Smith" -AccessRights FullAccess -InheritanceType All
   

Step 5: Copy the contents of the original mailbox to the new mailbox

To copy the contents of the original mailbox to the new mailbox, follow these steps:

1. Create a new Outlook profile that opens the new mailbox by using an Exchange (MAPI) account.

2. Start Outlook, and then open the new mailbox.

3. Add the original mailbox as an IMAP email account to the profile.

   For example, add the John Smith 2 mailbox as an IMAP email account to the profile.

4. When Outlook is open and both mailboxes can be accessed, select all the messages in the Inbox folder of the IMAP account, and copy them to the Inbox folder of the Exchange (MAPI) account.

   Note

   This action causes a MIME-to-MAPI conversion to occur. This should fix most item-level corruption of the messages.

5. Repeat step 4 for each folder in the mailbox.

6. When you finish copying all folders to Exchange (MAPI) account, remove the IMAP account from the profile.

7. In the same profile, open the original mailbox that was renamed in step 2 as an Exchange mailbox, and then drag the Calendar, Contact, Notes, and any other non-mail items from the original mailbox to the new mailbox.

   For example, open the John Smith 2 mailbox, and then drag non-mail items from the John Smith 2 mailbox to the John Smith mailbox.

Status

This is a known issue. Microsoft is currently investigating the issue and will post more information in this article when it becomes available.

More information

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