Solved: Cannot expand the folder. The set of folders cannot be opened.

I recently had the experience of migrating a client to Office 365. While most things went smooth, one user who was using Outlook 2007 wasn’t able to open one of the shared mailboxes. Every time she tried to open the file, the following error message would appear:

Cannot expand the folder. The set of folders cannot be opened. Microsoft exchange is not available. Either there are network problems or the exchange computer is down for maintenance.

I tried removing her profile and rebuilding it again, but to no avail. I was able to open the inbox using Outlooks option of File > Open & Export > Other Users Folder. I was also able to open the mailbox it in OWA.

In the end, the problem was related to the AutoMapping function of Exchange and Outlook. To solve the problem I had to do the following things:

1. Connect to O365 using your usual Powershell Connection lines:

$LiveCred = Get-Credential
$Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri -Credential $LiveCred -Authentication Basic -AllowRedirection
Import-PSSession $Session

2. Remove FullAccess permissions for the affected user from the shared mailbox

Remove-MailboxPermission (SharedMailbox) -User (UserAccount) -AccessRights FullAccess

3. Add Full Access permissions back on, but make sure you set AutoMapping to FALSE!

Add-MailboxPermission (SharedMailbox) -User (UserAccount) -AccessRights FullAccess -AutoMapping $false

4. Use Outlook to add another user’s mailbox by editing the account and adding the user by choosing (in Outlook 2013) File > Account Settings > Change > More Settings > Advanced > Add. The dialogue should look like below. Simply add the user’s in the Add dialogue and you should be good to go!


Share on Facebook0Share on Google+0Share on LinkedIn0Tweet about this on Twitter0Pin on Pinterest0Email this to someone


  1. I have exactly the same problem with Exchange 2010 and Outlook 2010/2013.

    Thanks for your solution !

    • Glad it helped and that someone reads my articles. :-)

      • I have a some what similar issue. We have a client running server 2012 with exchange 2013. All users in that location are using office 2010. They have another location in Iowa and that user can connect to exchange and access email fine through office 2013 however he gets that message when trying to open public folders which is where their team calendar resides. They connect through a VPN tunnel with a Cisco RV042 on both ends. I have tried opening ports on the firewalls, creating a new profile and nothing works. I am baffled!

    • Worked for me too. I was using the Console to do this and it looks like it automagically automounts the mailbox when you grant the permissions. It worked for a while, then just suddenly stopped working. Thx.

  2. Worked for me too, thanks!

    • Happy to help! Ironically, I used this article to re-solve this problem at the same client just the other day.

  3. Thanks Joseph,

    This remove and readd was a fix for delegated permissions and Outlook users on an 2007 to 2010 Exchange migration. Those in 2010 using Outlook 2007(and maybe other clients?)had the problem but after we did this process they could expand folders. I would note that SharedMailboxUser = the target account and User2 is the person that needs the permission to it.

    • That’s a great clarification. I’ll update the code to be a bit more clear on those descriptions. Thanks!

  4. I’m facing the similar issue but the difference is I m on exchange server 2003, can you suggest how can I resolve this issue ???

    • Sandy,

      I’m not quite sure what to look for there other than making sure that the permissions on the mailbox are correct. In on premise Exchange environments, that’s usually what I’ve seen. Maybe review those settings?

  5. should this work for adding full access permission to an AD group, rather than individual users?

    • You know, that’s a really dang good question and it sounds plausible, but I have no idea. Anyone else able to weigh in here?

  6. Thanks!!! This solved my problem!!!

  7. We often give supervisors full access to termed employees mailboxes. Most of the time its’s successful, but I’ve had a couple that get the cannot expand folder error even after giving them full access and adding the email account to their Outlook. Any tips for resolving this? TIA

    • What version of office are they running, Outlook specifically?

  8. Thanks so much Joseph, this worked after a lot of failed attempts, it had initially worked for me but I deleted thinking I had done something wrong, when I tried again kept getting that error. Followed your steps and it worked! :)

    • Eli, no you aren’t crazy. They just suck at making clear error messages. Glad to have helped!

  9. Good Day,

    Your solution worked nicely, but I can’t help feel like having to use Powershell to correct a permissions issue is a bit of a step backwards from the way things used to be.

    You have to wonder who the guy at Microsoft was who put in the, “Let’s use DOS commands instead of the Windows GUI we developed” memo.

    Anyway, enough ranting. Thanks for your fix.

    • The use of a scripting language on the back end is incredibly powerful and a wise move on their part for sure, but omitting a GUI equal does indeed seem like a departure from what has made Microsoft so mighty in the first place. And so it goes when they don’t listen to their customers… Happy to help.

  10. I’m having the same issue. Just migrated a few months ago. Using Exchange 2007 on premise and Outlook 2013. Just one user seeing that message for a shared mailbox. I tried your suggestion and still the same. Very weird!

  11. This can resolve the problem, but the question is how to get the auto-map fixed? I really like that feature in Exchange 2010 and don’t understand why it’s broken on the server I’ve recently inherited.

    • Unfortunately, I have no idea. It seems like a simple thing, but nothing I’ve tried actually fixes the root of the problem.

      • I have issue with outlook, while giving the delegates access user 1 to user2, After giving all permission, In user 2 outlook user 1 name Appeares, But i try to expand the folder it says ” can’t expand the folder”. Pls help on the same.

        Thank you :-)

  12. I have the same on Exchange 2010 and Outlook 2010, one of the user has that problem all the sudden. I try to recreate the mail profile and ost, but no help. Your solution work for me, you have save my day.

  13. Do I need to load a particular module to get the Remove-MailboxPermission cmdlet to work? As of right now I’m getting an error that it doesn’t recognize the cmdlet. Specifically, my error reads:

    “The term ‘Remove-MailboxPermission’ is not recognized as the name of a cmdlet, function, script file, or operable program.”

    I’m using a domain administrator account, and running the PowerShell ISE (PowerShell v. 3.0, btw) as administrator. Any idea why this isn’t working?

    • It sounds like you don’t have the O365/Exchange powershell commandlets loaded. I can’t remember what you need to install, but it essentially gives you access to those commands.

  14. Thanks. We have on premise Exchange 2013 and this worked for us, too. Odd variations.

    Shared mailbox created via ECP along with full access permissions for several users. My full access permissions were inherited.

    I connect the mailbox to Outlook 2010, restart it, and get the error when trying to expand the mailbox.

    I run the first command on my account and get the warning that it did not remove my permissions because they are inherited. I run the add command with the -AutoMapping $false parameter. It completes successfully. I don’t run any more commands.

    We check this out on a colleague’s Outlook who I had also added to Full Access via ECP (not inherited) His works fine.

    Either, I fixed his with the command I ran on mine (unlikely), or the incorrect AutoMapping parameter is only inserted for accounts added during the mailbox creation (my inherited permissions) and not for accounts added with the subsequent “Properties” edit.

    Strange, but I am not questioning this now that it works. Thanks again.

  15. I am having the same issue but only in sporadic cases. Some users can access some mailboxes and others cannot. Removing and re-adding the permission with automapping:$false does not resolve the issue for them. Some mailboxes we are trying to access are recipient mailboxes as well. If the same user is on office 2010 its fine but only certain mailboxes will work on 2013. Any ideas?

    • With 2010 and 2013 there are some issues with compatibility. First of all…your 2010 Servers need to be updated. Specifically Also, your outlook version if very important. Specifically you need at minimum January 2015 CU for outlook 2010 and 2013. You will find documentation on the changes in these CU’s, but there are changes regarding interoperability. You also did not specify if you are using kerberos. As for the automapping issues in this article, we are working with MS to address the errors.

  16. I can add an additional mailbox using Joseph’s job-aid from above and see all the folders for the second mailbox. But, all my “rules” for the second mailbox are NOT an option.

    If I add an additional mailbox from:

    file/Info/Add Account/Add New Account

    I get the “Cannot Expand the folder”.

    The second mailbox is a Proxy mailbox and have full permissions.

    The second mailbox works great in OWA!


  17. Same issue here. We have a shared mailbox created in the portal. Permissions are set; some people can expand it, others cannot. All can open it in OWA. Tried the commands and it did not resolve the issues.

    Tagging so I can check back later to see if a full resolution has emerged.


Submit a Comment

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>