Cannot expand the folder. the set of folders cannot be opened shared mailbox

As the administrator of an Office 365 shared mailbox, you have the ability to allow other individuals to receive and respond to email messages and meeting requests sent to that mailbox. You determine the level of access these individuals have. You can grant them permission to read items in the mailbox or to read, create, change, and delete items.

NOTE: The instructions below refer to a Windows 10 installation of Outlook.

Granting Access to a Shared Mailbox

  1. Open Outlook.
  2. In the Navigation Pane, locate the shared mailbox and right-click on the root mailbox name.
    • Note: You must select the root level of the mailbox, not a sub-folder such as Inbox.
  3. Select Data File Properties….
  4. Select the Permissions tab.
  5. Select Add.
  6. Enter the name of the person whom you want to have access and then select their name in the search results list.
  7. Select Add, and then select OK.
  8. In the Permissions tab, select the individual you have just added.
  9. Use the Permissions Level: drop down to select the level of access they should have.
  10. Select OK.

Granting Access to Shared Mailbox Folders

  1. Open Outlook.
  2. In the Navigation Pane, locate the shared mailbox and expand it using the arrow to the left of its name.
  3. Right-click on Inbox and select Properties….
  4. Select the Permissions tab.
  5. Select Add.
  6. Enter the name of the person whom you want to have access and then select their name in the search results list.
  7. Select Add, and then select OK.
  8. In the Permissions tab, select the individual you have just added.
  9. Use the Permissions Level: drop down to select the level of access they should have.
  10. Select OK.
  11. Repeat steps 3 - 10 on any other mail folder the individual may need access to. We recommend granting access to Drafts and Sent Items at a minimum.

Modifying Access to a Shared Mailbox Folder

  1. Open Outlook.
  2. In the Navigation Pane, locate the shared mailbox and expand it using the arrow to the left of its name.
  3. Right-click on Inbox and select Properties….
  4. Select the Permissions tab.
  5. Select the individual you wish to modify.
  6. Use the Permissions Level: drop down to select the level of access they should have.
  7. Select OK.
  8. Repeat steps 3 - 7 on any other mail folder the individual may have access to.

Removing Access to a Shared Mailbox

  1. Open Outlook.
  2. In the Navigation Pane, locate the shared mailbox and right-click on the root mailbox name.
    • Note: You must select the root level of the mailbox, not a sub-folder such as Inbox.
  3. Select Data File Properties….
  4. Select the Permissions tab.
  5. Select the individual you wish to remove.
  6. Select Remove.
  7. Select OK.
  8. In the Navigation Pane, locate the shared mailbox and expand it using the arrow to the left of its name.
  9. Right-click on Inbox and select Properties….
  10. Select the Permissions tab.
  11. Select the individual you wish to remove.
  12. Select Remove.
  13. Select OK.
  14. Repeat steps 9 - 13 on any other mail folder the individual may have access to.

Oulook Permission Levels Defined

With this permission levelUsers can
Owner Create, read, modify, and delete all items and files, and create subfolders. As the folder owner, you can change the permission levels that other people have for the folder. (Does not apply to delegates.)
Publishing Editor Create, read, modify, and delete all items and files, and create subfolders. (Does not apply to delegates.)
Editor Create, read, modify, and delete all items and files.
Publishing Author Create and read items and files, create subfolders, and modify and delete items and files that you create. (Does not apply to delegates.)
Author Create and read items and files, and modify and delete items and files that you create.
Contributor Create items and files only. The contents of the folder do not appear. (Does not apply to delegates.)
Reviewer Read items and files only.
Custom Perform activities defined by the folder owner. (Does not apply to delegates.)
None You have no permission. You cannot open the folder.

How do you fix Cannot expand the folder the set of folders Cannot be opened the attempt to log on to Microsoft Exchange has failed?

Following are a few effective solutions to fix the error “Outlook the set of folders cannot be opened” are as follows:.
Launch Outlook in Safe Mode..
Update the Outlook application..
Recreate your Outlook Profile..
Turn off Compatibility mode in Outlook..
Repair Office Installation..
Fix Outlook..
Repair PST Using ScanPST Tool..

How do you fix Cannot open the Outlook window the set of folders Cannot be opened?

Fix “The Set of Folders Cannot be Opened” Error in Outlook 2016,....
Start Outlook in Safe Mode. ... .
Create a New Outlook Profile. ... .
Start Outlook from the Taskbar. ... .
Use an App Password for Outlook. ... .
Install the 64-bit version of Office. ... .
Remove your Account from the Mail App. ... .
Remove . ... .
Repair Outlook Data Files..

Why can't I expand the folder pane in Outlook?

Use the Pin Icon Select the '>' button to expand the Folder Pane. Then click the pin icon to pin the Folder Pane. That way, it will stay expanded even when you click outside the pane.

What does it mean when Outlook says the set of folders Cannot be opened?

According to users, The set of folders cannot be opened error can appear due to XML files in Outlook's directory. These files can become corrupted causing the problem to appear. To fix the issue, you need to delete those files manually.