Fix Shared Mailbox Folders Not Showing Up in Outlook 365

Users often complain about shared mailbox folders not showing up in Outlook 365 when they see that the shared mailboxes are missing from the navigation pane. Despite a thorough scan of their account, the users cannot pinpoint the location of a previously visible shared mailbox.

Since shared mailboxes are a vital part of Office 365’s collaboration tools, their absence can significantly disrupt professional workflows.

Therefore, we have made this guide which provides detailed instructions to help you restore visibility of shared mailboxes and their subfolders. However, before we begin it is better to lay out the possible causes of this issue first, as this will make the solutions easier to understand.

Reasons Why Shared Mailboxes Disappear in Outlook

Here is a list of the most common situations:

Technical Glitch/Sync issues: Under poor network conditions or when running older devices Outlook can struggle to reflect all changes instantaneously.

So we recommend waiting a few minutes and letting the issue resolve automatically. If this does not work, close the current instance and reopen the app again. Pair this with a login-logout activity.

Cluttered Folder Structure: The biggest culprit for users is a clumsy Outlook dashboard. Anything from improper hierarchy to loads of unnecessary subfolders can fill up the navigation pane. This makes it quite difficult to locate the missing shared mailbox.

Access not given: Admins may have mistakenly chosen the wrong person while assigning permissions. There is a high chance for this to happen if there are multiple people with the same name. If you think a mistake has been made, inform the admin about the issue.

Shared Mailbox Limit Breached: Even though there is no hard limit on how many people can have access to a shared mailbox, it is an industry-standard to keep the number below 25. Moreover, shared mailbox oversubscription is known to cause many issues, including it becoming invisible.

Access revoked: It is also possible that earlier a user had access to the shared mailbox but due to some internal policy changes, it was taken away. This will result in the shared mailbox disappearing on its own. Moreover, if users believe this is the case, then they should take a look at their primary mailbox, it should contain a message informing them about the changes.

Shared Mailbox Deleted: Other than that, the permanent removal of a shared mailbox from the admin center is why users can’t find it. This can also occur if a shared mailbox is reconverted to a user mailbox.

Undo Shared Mailbox Folders Not Showing up in Outlook Classic

There are 3 methods available at User Level:

1. Generate and Check Logs

• Step 1. Launch Outlook Classic.
• Step 2. Go to File > Options > Advanced > Enable troubleshooting logging > click OK.

• Step 3. Restart Outlook.
• Step 4. Check logs in C:/Users/UserName/AppData/Temp or %localappdata%/Temp folder.
• Step 5. Finally, analyze logs to identify and resolve Shared Mailbox issues.

2. Manually Add Shared Mailbox Folders Not Showing up in Outlook 365 Classic

• Step 1. In Outlook, go to File > Account Settings > Account Settings.
  
• Step 2. Under the email tab, double-click the email and select “More Settings“.
• Step 3. Then, enable “Download Shared folders” in the Advanced tab. Hit Apply.
  
• Step 4. Press OK in the Popup.
  
• Step 5. Finally, click OK again and close all windows.

3. Is Shared Mailbox Still Not Visible in Outlook? Try to Recreate Profile

• Step 1. Close Outlook and open the Control Panel > type Mail in the Search bar.
• Step 2. Then, Click On Mail (Microsoft Outlook) > Show Profiles.
  
• Step 3. Tap Add, put in a Profile Name, and Hit OK.
  
• Step 4. Type Name, Address, Password (twice), and Press Next.
  
• Step 5.  Let the configuration happen then click Finish.
  
• Step 6. Then, re-launch Outlook with the new profile.
• Step 5. Wait until the profile syncs and then view the Shared mailbox status again.

Use Outlook Web as a Possible Solution

Note that if users don’t solve the issue then they won’t be able to export the distribution list to Excel Office 365 at all.

• Log in to Outlook Web and hover over the Folders tab in the left side pane.
• Click on the three dots
• Select “Add shared folder or mailbox”

• Put in the name of the shared folder and select it from the drop-down then press Add.
• The Shared Folder should appear in the left-hand pane alongside other tabs.

Other alternative approaches include:

• Turning off Shared Mailbox Caching.
• Checking/disabling add-ins.
• Making sure the client is up-to-date.

If Shared Mailbox Missing from Outlook Web
The same steps can be replicated in Outlook’s new desktop variant, as their GUI is almost identical.

For admins, the steps differ a bit:

First log in to the admin center > toggle Teams & groups > Go to Shared mailbox > Click on Add a Shared Mailbox > type the name and set the domain > Hit Save changes.

Populate the member list and ask the members to add the mailbox in their individual account.

Fix Shared Mailbox Missing from Outlook Mobile App

First up ensure that you have logged in via a business account and not a private one. This is because the private account cannot add/view shared mailboxes. Then proceed with these steps:

• Tap on your profile icon > Hit the + button
• Select “Add a shared mailbox option” from the popup
• Type the shared mailbox name, then Hit Continue.

Recheck all the mailboxes below the home icon if everything is working, you should find your shared mailbox right there.

If you face issues like shared mailbox folders not showing up in Outlook 365 again, then use the series of steps given below. These are valid for both Android and iOS devices.

• Close Outlook and remove it from the background.
• Then, go to settings and locate the app manager.
• Find Outlook and force stop the app manually.
• Then, like a factory reset on the Outlook app, clear out all app data (not just the cache).
• Finally, open Outlook again > Add all accounts

This should make the shared mailbox appear on your Outlook mobile app.

How Admins Can Use PowerShell to Fix User Shared Mailbox Not Showing in Outlook New or Classic?

If you are an admin whose users complain about missing shared folders in M365 then you can deploy the custom scrips provided here to resolve the problem.

Step 1: Create a CSV Map of all Shared Mailboxes and Corresponding Users

Admins should begin the task by identifying which shared mailboxes are not appearing in Outlook.
To make the process easier we have a sample PowerShell command that can retrieve all shared mailboxes along with their assigned permissions, and export the results in CSV:

# Define the CSV path
$CsvPath = "C:\Temp\SharedMailboxPermissions.csv"

# Collect permissions dynamically
$ExportData = @()
Get-Mailbox -RecipientTypeDetails SharedMailbox | ForEach-Object {
$SharedMailbox = $_.PrimarySmtpAddress
$Permissions = Get-MailboxPermission -Identity $_.Identity | Where-Object {
($_.AccessRights -eq "FullAccess") -and ($_.IsInherited -eq $false)
}
foreach ($Permission in $Permissions) {
$ExportData += [PSCustomObject]@{
SharedMailbox = $SharedMailbox
User = $Permission.User
AccessRights = ($Permission.AccessRights -join ",")
}
}
}

# Export to CSV
$ExportData | Export-Csv -Path $CsvPath -NoTypeInformation -Encoding UTF8
Write-Host "Permissions exported to $CsvPath"

This command identifies the shared mailboxes and lists users with only the Full Access permissions. You may edit the script to broaden the search/ list criteria to include other access rights levels.

Now that you have the documentation for all shared mailboxes, we can move on to the next step.

Step 2: Revoke and Reassign Permissions
This is the step where we first disconnect and then reconnect users with their corresponding shared mailboxes but keep auto mapping disabled.
It is done to rule out the possibility of a non-working auto-discovery feature. Make use of the same exported CSV file for this process:

# Import the CSV
$Permissions = Import-Csv -Path "C:\Temp\SharedMailboxPermissions.csv"

# Loop through permissions and update
foreach ($Permission in $Permissions) {
$SharedMailbox = $Permission.SharedMailbox
$User = $Permission.User

Write-Host "Processing $User for $SharedMailbox"

# Revoke permissions
Remove-MailboxPermission -Identity $SharedMailbox -User $User -AccessRights FullAccess -Confirm:$false

# Reassign permissions without AutoMapping
Add-MailboxPermission -Identity $SharedMailbox -User $User -AccessRights FullAccess -AutoMapping:$false

Write-Host "Permissions updated for $User on $SharedMailbox"
}

The final step is to be done by users. Instruct them to manually add the shared mailbox to Outlook guaranteeing a solid connection. Save these scripts to quickly detect and diagnose shared mailboxes disappearing from Outlook in the future.

Advanced Solutions to Shared Mailbox Folders Not Showing up in Outlook 365

If you suspect that any one of your add-ins is the reason why you can’t see or interact with the shared mailboxes try starting Outlook in safe mode

• Force close current Outlook instance.
• Press Windows key + R.
• Enter Outlook.exe /safe, and press OK.
• In case you see an error type the full path to where the Outlook executable file exist and open again.

You have a particular build of Outlook then the issue may be specific to your build.

Check Build Number and Deploy a Registry Level Fix

• Outlook: File > Office Account (or Account) > About Outlook.
• If it says Outlook Version 2202 (Build 14931.20604) then either update to the latest version or perform a
• Registry level fix.
• Close Outlook.
• Press Windows + R > Type Regedit > Press Enter.
• Go to: Computer\HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Profiles.
• Select the profile for which shared mailboxes are invisible.
• Find key 0102663e (Ctrl+F).
• Delete 0102663e key.
• Close Registry Editor.
• Restart Outlook.
• Check if the issue is fixed or not.

What to Do After Successfully Retrieving Shared Mailboxes in Outlook?

The answer to that is simple, create a backup. Having an offline copy of regular mail is common but the same can’t be said for the shared mailboxes. As multiple users have access to this entity, every user is under the impression that someone else has a backup.

However, if every shared mailbox access holder thinks like that, then no one prepares a backup and in case of a mass missing request, all the shared mailbox conversations are lost for good.

Don’t worry, you need not download each email individually; instead, there is a way better solution tailor-made to make the backup process as easy as possible. It is the Systools Office 365 Backup tool. This piece of software comes with all sorts of filters and features to create an offline copy of every important thing inside a shared mailbox.

Download Now Purchase Now

Especially if it’s the admin who has lost access, so use this straight path to diminish the effect of missing shared folders.

Download a copy > Choose Endpoints > Select Workload > Apply Date Filter > Validate Source > Pick a Destination > Map Users > Preview and Backup.

If nothing works you can always Export Office 365 Shared Mailbox to PST file format directly from the cloud.

Conclusion

After this read, users no longer have to struggle with shared mailbox folders not showing up in Outlook 365 web, mobile, and desktop applications. Moreover, here we laid out all the possible reasons and gave users a multi-pronged approach to deal with the missing mailbox issue. Even after the users are able to successfully locate the shared entity, it’s important to have a backup of the file in case of similar emergencies. This requirement was also taken care of with the help of the automated solution.

Frequently Asked Questions on Fixing Shared Mailbox Folders Not Showing up in Outlook 365

Can the size of a Shared Mailbox impact its visibility in Outlook?
Shared Mailboxes can expand up to 50 GB in size; however, they don’t consume the storage space of user accounts. Rather, Microsoft allocates separate space for them. Shared mailboxes are accessed via a network connection, so contents may not load properly is the shared mailbox is too big.

Is it possible that when multiple users access a shared mailbox simultaneously it disappears for some users?
Although Shared Mailboxes are designed for simultaneous use, they have a strict upper limit. The moment the number of users exceeds 25, performance degrades, which often means the Shared mailbox goes missing for some users.

What is the upper limit of shared mailbox count per user?
There isn’t a hard cap on the number of shared mailboxes that a M365 user can be part of. However, having too many shared mailboxes may cause some of them to disappear from Outlook.

Can an admin change the primary email address of a Shared mailbox, and what happens to User Access when such a change takes place?
Yes, admins have full authority to change the Shared mailbox address whenever business requirements necessitate. Moreover, if a Shared mailbox was originally a user mailbox, admins may revert it back and make it a single-user access mailbox. This also prevents other users from finding the Shared mailbox in their Outlook app.

Are there any preconditions for using the PowerShell script-based method to fix the shared mailbox not showing in Outlook New?

Yes,

1. Only use the O365 admin account.

2. Use

Set-ExecutionPolicy RemoteSigned

to access PowerShell as administrator.

3. Install required modules.

4. Connect to Exchange Online using PowerShell:

$Credential = Get-Credential

to store credentials. Then:

Import-PSSession $Session