What would make a Shared Mailbox NOT show up in Outlook (2016, ProPlus C2R)?

[Brent Ellis]

What setting would make a Shared Mailbox NOT show up for a user?

User is using Office 365 ProPlus (click to run), version 2016 (first release deferred channel).

[#2]

Hiya,

If you are seeing the shared mailbox automatically add itself to the user with permissions Outlook profile, then it is being auto mapped. This is the default either via the portal or via PowerShell.

To remove auto mapping, remove and re-add the permission using PowerShell. This article here takes you through the process:

How to remove automapping for a shared mailbox in Office 365

Steve

[#3]

(By the way, if you are asking about the other way around, i.e. why isn't it automatically mapping) then the first point of call is to remove and re-add the permission. For example, if you move a mailbox from on-premises, this could explain why although it kept the permission auto mapping isn't working.

[#4]

Option 2 is what I am asking about, permission has been removed and re-added a few times now (over the course of a few days). It works for other people, including myself.

I am curious if it is a setting perhaps, but before we go digging around his computer and Outlook settings, would like to know what we should be looking for.

[#5]

The link above should show you the only setting service-side available to control it. By default, it adds the automapping, which should mean just a remove and re-add should ensure that it has been configured the way you intend it to work.

The setting itself will be stored in Office 365 within an AD that sits behind your Exchange Online environment. Technically it works the same way as on-premises. 

After making the change, you should expect to see the mailbox auto-map within at the most an hour, but within 10-15 minutes would be normal if you re-launch the client.

If you want to verify Outlook is receiving the correct details, you can use the Test Email Autoconfiguration to retreive the Autodiscover XML, which will show if the mailboxes to auto map are being provided by Exchange Online.

To do this, Ctrl-right click the Outlook icon in the notification area of the taskbar, and choose Test email autoconfiguration, enter the email address and password and only leave Autodiscover ticked. Once it completes, you will see a Result, Log and XML tab. Look in the XML tab and scroll down to the bottom and see if you see an <AlternativeMailbox> section listing the Shared Mailbox.

If it is listed, it's the client (or connectivity from the client when it does another Autodiscover to map the shared mailbox), if isn't listed, then it's something to do with the automapping not being pushed through server side.

Steve

[#6]

A couple times a user here hasn't seen the Shared Mailbox in desktop but did in OWA, we would delete their Outlook profile and recreate it. That, for us at least, got the Shared Mailbox to show up.

[#7]

So a bit more clarity (user is in Europe), was able to determine the mailbox WAS showing up, just couldnt be used.

The setting "use exchange cached mode" was not checked, which as soon as it was, user was able to start seeing emails and folders.

[#8]

If the mailbox was showing up, then the shared mailbox was pushed through autodiscover to Outlook client. Next step performed by Outlook is to run autodiscover on the address of the shared mailbox and this is where is probably failing.

You can run test email auto-configuration on the address of the shared mailbox, without any credentials. If prompted for credentials, type in the upn and password of the user having permissions over the shared mailbox.

If you have a hybrid environment (autodiscover pointing to on-prem) and the shared mailbox was created directly in cloud, then this is the cause.
https://support.microsoft.com/en-us/help/3129334/users-in-a-hybrid-deployment-can-t-access-a-shared-...

[#9]

Hi
if you want a Shared Mailbox not to appear in outlook, you need to disable auto mapping.

Connect power shell and run the command below.

Add-MailboxPermission -Identity spercoco@techsupporto365 -User 'alex' -AccessRights FullAccess -InheritanceType All -AutoMapping $false

[#10]

I just had the issue where shared mailbox will not show up in outlook. Upon checking the settings in Office 365 admin portal (Activ Users/Mail Settings/Email Apps) the MAPI and IMAP settings were disabled. After enabling, and restarting the outlook few times, shared folder became available. 

[#11]

I found this via a top search result, only my issue was for an on-prem to on-prem migration (Exchange 2010 to Exchange 2016.) I figured I'd tack on to this older ticket in hopes it helps someone else. Steve's mentioning Autodiscover sent me down the right path.

A user had been migrated to Exchange 2016 a week prior and was working fine, including using two mailboxes (that were user mailboxes but he had full access/ sendas permission.) After migrating the two secondary mailboxes, one was opening and the other would just say "Cannot expand the folder. The set of folders cannot be opened. Microsoft Exchange is not available. Either there are network problems or the Exchange server is down for maintenance."

I re-created the user's local Outlook profile and while the working secondary mailbox showed up, the other one was missing completely. I checked Autodiscover for his email account, and saw that he had both secondary accounts listed. I then stumbled across this thread.

Steve & Victor's suggestion about Autodiscover lead me down this path:

I checked Autodiscover for the secondary mailbox that wasn't working, and it couldn't find the config. I then recycled the MSExchangeAutodiscoverAppPool on that mailbox's server, and after a minute Autodiscover for that account worked.

I had the user close and open Outlook again, and after restarting again (due to the prompt post-migration), it showed up and worked.