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Disable MAPI over HTTP for Outlook Clients

For users experiencing problems connecting Outlook clients to Exchange Online/Office 365, the steps below are commonly recommended by Microsoft Support as an alternative configuration of Outlook. Please consult your local IT support if you are not familiar with the Windows Registry or the steps outlined below.


Steps to disable MAPI over HTTP (Download and Import Option)

  1. Exit Outlook if it is running.
  2. Download MAPIoverhttp_disable.zip file and save it locally on your computer.
  3. Using Windows Explorer, navigate to the location you saved the MAPIoverhttp_disable.zip file. Extract the contents of the zip file and navigate to the extracted location. Locate and double-click the MAPIoverhttp_disable.reg file.
  4. Click "Run" when presented with the security warning concering the reg file and confirm that you'd like to make the change if additional confirmation messages appear.
  5. Click OK when the message appears that the reg files has been imported.
  6. Start Outlook.

Note: If you would like to enable MAPI over http, you can use the MAPIoverhttp_enable.zip file and use the same steps mentioned above.


Steps to disable MAPI over HTTP (Manual Option)

  1. Exit Outlook if it is running.
  2. Open the Registry Editor, by clicking on Start and typing "Regedit.exe".
  3. Locate and select the following key in the registry:
    HKEY_CURRENT_USER > Software > Microsoft > Exchange
  4. Check for "MapiHttpDisabled". If "MapiHttpDisabled" does not exist, right-click in the right window, select New > DWORD, replace "New Value #1" with "MapiHttpDisabled"
  5. Right-click "MapiHttpDisabled" and the click Modify.
  6. Change the Value to 1 and then click OK.
  7. Close the Registry Editor.
  8. Start Outlook.