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Unable to access Public folder via outlook in Exchange 2010 environment.

I was tiredly walking into work today and was praying to have a nice shift. Then the user phone line started buzzing and I picked the call heart broken.

Desktop support: Users are unable to access Public folder via outlook.

Me: May be the outlook profile, did you check it thoroughly?

Desktop support: I tried everything with the outlook profile, but now multiple users are reporting the issue. This is the error we get:

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

Me: Is it just outlook? Does accessing public folders via OWA works fine?

Desktop Support: Yes, its jus outlook. OWA works absolutely fine.

Me: Ok, I will take a look at the server and get back to you shortly.

Steps taken?

  • Verified that the Mailbox databases are pointing to correct Public Folder database.
  • Verified that the RPC Client access service is running on the CAS/HUB server.
  • Something hit my mind at this point, and I took a look at the “RPC Client access service” in the mailbox server, it was stopped.
  • I tried to restart it and bang!!! PF access thru outlook restored.

Logic applied:

We know that “RPC Client access service” in the CAS/HUB servers do a lot of operations pertaining to managing client connections for exchange. But, why do we need this service in the Mailbox server?

“RPC Client access service” in the mailbox server is used for none other than public folder access. When the outlook client queries for Public folders, it directly connects to the PF server (You can view it by checking the “Connection status” from outlook). This request is taken care of by the “RPC Client access service” in the mailbox server. In any case if this service is stopped/Hung, then we may see the above problem.

Smitha J
Team @MSExchangeGuru

9 Responses to “Unable to access Public folder via outlook in Exchange 2010 environment.”

  1. Stef Says:


    we had a similar issue on our infrastructure.
    Our exchange server stopped accepting PF connections

    We have to implement the following KB
    Outlook client applications cannot connect to public folders after you install Exchange Server 2010 SP1 (


  2. Shiva Says:

    HI Friend,

    I am facing of one issue in exchange server 2010, Its regarding, one of the mailbox users is unable to expand Public folder items from only Microsoft outlook,

    1) I have tried to open the same thing in OWA, but there its working fine,
    2) Also i have taken the mailbox control for myself, its working fine.
    3) i have tried to configure the only affected user profile in multiple machines, but its not working.
    4) Finally we found that, only its happening from Microsoft outlook,

    Request :

    If anyboudy expert in Exchange server 2010, please help on this, It would be appreciated…………………..

    Thanks & Regards

  3. Shivappa Hosamani Says:

    Answer for this.

    1) For restarting the Information store of Exchange servers. issue can resolve.
    3) Can increase the MAPI session.issue can resolve.
    3) Can kill the single user MAPI session.issue can resolve.
    4) Can restart the servers ( Not mandatory)

    These are all troubleshooting steps for PF issue.

  4. David Wong Says:

    Thank so much for this post. Save me a lot of time and I was a little freak out. I have Exchange 2010 SP1. I initiated .\MoveAllReplicas.ps1 on Friday. On Saturday morning, I went to take a look a the Pubilc folder and received “Cannot expand the folder. The set of folders cannot be opened. Microsoft Exchange is not available. Either there are network problems or the Exchange is down for maintenance.” I checked to make sure all mailbox database was using the correct default Public Folder datastore under properties under each mailboxes. I got freaked out, luckily I found this post, which saved me a lot of time for sure. I started the “RPC Client access service” and Pubilc Folder access were working again.


  5. Gary Says:

    Had this issue today and restarting the RPC Client access service did the trick. Much appreciated!!

  6. Nicholas Choate Says:

    We have Exchange 2010 SP1 installed on our server. My existing employees running Outlook 2010 & 2007 are able to access Public Folders without issues. I have purchased 4 new Dell Desktops with Outlook 2013 and they are all able to connect to Public Folders without issues.

    I purchased Office 2013 Professional Plus Open Value licenses and have started to upgrade all of our 2010 and 2007 desktops to Office 2013. Once upgraded they are able to connect to the Public Folders without issues however if I install Office 2013 Professional Plus on a new computer as a new installation we are unable to access Public Folders. The Public Folders and Notes are grayed out. Any Idea why this is happening?

  7. Rajesh Says:

    Restart of RPC CA Serice on mailbox server did a wonderful job.

    Thanks and much appreciated!!!

  8. Beth Says:

    I am having this problem this morning after pushing updates over the weekend. I have checked the RPC Client service and it is running. I restarted it just to see and still getting the error code.

  9. Jatin kakkar Says:

    Guys I have two issues with public folders in office 365

    #1. I cannot add rights through the office 365 portal.
    #2. I have users getting locked messages and not being able to move/delete items in the public folders. I did not have this issue on the old system.

    outlook client is office 2013 pro plus

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