Outlook - Exchange Connection Error

I have a single user having this issue, all other users are working properly.

Problem started when we migrated from Exchange 2007 to Exchange 2013

When opening Outlook 2013 to connect to On-Prem Exchange 2013 server, getting the following error:
Microsoft Outlook
Cannot Start Microsoft Outlook. Cannot open the Outlook window. 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.

Troubleshooting already attempted
  • Removed Users Exchange account, and recreated = Problem still happening
  • Moved Users mailbox to different Exchange Database
  • Problem occurs on different system (follows user)
  • Only occurs with the single users, all other users work properly
  • Outlook Web Access works properly for the user.
Michael FergusonSystems EngineerAsked:
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Problem occurs on different system (follows user)

Does the user have a roaming profile?
Michael FergusonSystems EngineerAuthor Commented:
Not a Roaming Profile
I was going to suggest this
Try to reset the navigation pane and check if it helps.

    Ensure Outlook is closed,
    Hold Windows key + R.
    Copy and paste, or type the following command in the Open box, and then press Enter:

Outlook.exe /resetnavpane

Note: There is a space between Outlook.exe and /resetnavpane.

If it were a roaming profile. you might try it just for grinns. you never know.
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It's most likely a corrupt OST file so read the reply's on the site particularly #3 from Phil.
This is a youtube video on how to fix the problem.
The example shows adding a new profile but you can also delete it and and new.
Tim EdwardsIT Team Lead - Unified Communications & CollaborationCommented:
Is it a physical machine or virtual? Do you have any profile management. If OWA is working and it is the specific user have you tried to repair or reinstall Office 2013 on that specific machine?
Lisa MillerCommented:
The common fixtures that can be applied as a workaround in order to know how to fix Cannot Start Microsoft Outlook. Cannot open the Outlook window. The set of folders cannot be opened. Microsoft Exchange is not available.


1. Open Task Manager and make right click on it otherwise press CTRL + ALT + DELETE
2. Have a look on all background processes;
a. Communicator
b. Ucmapi
c. Outlook
d. Or, Lync
3. Select the process which you want to end and press "End Task" button


1. Be sure there is no any background processes running and close Microsoft Outlook
2. Open Control Panel > Mail > Email Accounts > Email Tab
3. Select the email address which warning you and hit the Change
4. Be sure that Cached Exchange Mode option is not selected
5. Press the Finish tab and press Next tab

Technique 3: Run OST Integrity Check Tool/ Inbox Repair Tool

Know here how to run Inbox Repair Tool in Microsoft Outlook

Technique 4: Recreate OST File
1. Control Mail >> Mail >> Name of profile
2. Choose properties >> Email Accounts

3. Select the email address which warning you and hit the Change
6. In Advanced Settings, enable the Cached Exchange Mode
7. Click on OK to save changes and a new OST file will be created for that email

Apart from above fixtures I would like to suggest you a blog which will guide you about how to fix such type of issue.

Please refer this blog; http://www.ostpst.convertostpst.com/ost-cannot-be-accessed.html

Hope it might help you !!
Michael FergusonSystems EngineerAuthor Commented:
Thank you all for the suggestions, but the issue was not an OST as the problem was occurring across multiple systems.

  • Built an entire new AD User Account
  • backed up Mailbox with Export to PST
  • Disconnected email profile from broken AD Account
  • Assigned email address to new account (did not connect to disconnected mailbox)
  • Imported mail to new account.

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Michael FergusonSystems EngineerAuthor Commented:
no other answers lead to solution
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