Outlook 365 Keeps Prompting for Password After August 2017
In August 2017 Microsoft released another version of Outlook for Office 365 for PC that caused a major problem for people connecting to Exchange 2016 servers. This problems is all to do with the AutoDiscovery setup that Outlook uses. Microsoft appear to have set outlook to use their Office 365 servers as an initial point of setup configuration regardless of how you have configured AutoDiscovery.
The bottom line is that outlook keeps trying to authenticate agains office365 and not your own server. While this is a known issue, as of January 2018 it has not been fixed in the next version of Outlook.
There are two fixes, and either one should work. We suggest Fix 1
First one involves setting a registry entry on the computer experiencing the issue. To fix this issue, create a text file and copy/paste this text below.
Windows Registry Editor Version 5.00
Then save it, and rename it as ExcludeExplicitO365Endpoint.reg and run it (this will import the applicable registry key). ONLY DO THIS if you are using an Exchange On-Premise account, and not a Office365 or hosted exchange account.
The solution I’ve found to work and the only one to stop this annoying popup of “enter your password”, is to downgrade to a lower version of office update.here is a script i wrote, in case you need to push this to several computers.
C:\Progr~1\Common Files\Microsoft Shared\officeClickToRun /update user updatetoversion=16.0.8326.2107 1>officec2rclient.exe
this will take your office 2016 to update 8326.2107 where this issue doesn’t happen.nothing will show up on the screen, but give it about 10 minutes and restart the computer. check the control panel/ add-remove programs and make sure office is on the new (or actually old…) version.
Here is a link to some helpful information in running this update: https://support.microsoft.com/en-us/help/2770432/how-to-revert-to-an-earlier-version-of-office-2013-or-office-2016-clic
Outlook Slow and Unresponsive wiht MAPI over HTTP to Exchange 2016 Server
In our case the versions in question were found to be:
Outlook 2013 connecting to Exchange 2016 with MAPI over HTTP enabled.
The user reported that outlook was slow to open email, and unresponsive with searching in outlook.
The CTRL right click on the Outlook connection icon (bottom right) showed the connection was made with HTTP
It is reported that MAPI over HTTP which is a newer connection method of laterExchange servers and potential better and more reliable for devices connecting has some unreliabilities in some instances with earlier version of Outlook.
Our testing shows that later outlook versions and the Mac versions of outlook have no troubles at all.
IN Exchange 2016 it is possible to disable MAPI for a users mailbox. The issue this may have is that they could have other more recent devices such as phones and tablets that are enjoying the advantages of MAPI over HTTP. So rather than turning off MAPI for all their devices at the exchange server end. It is preferable to disable the connection on that users computer only.
This can be easily done using regedit.
Disabling MAPI over HTTP with Regedit
Log on to the proxy client where you installed the agent.
Use the credentials for the Windows account that you defined in the agent properties.
In Windows on the client computer, click Start, and then type regedit in the Search programs and files box.
The Registry Editor appears.
Expand HKEY_CURRENT_USER > Software > Microsoft > Exchange.
Right-click Exchange, and then click New > DWORD.
A new DWORD entry appears in the right pane.
Right-click the new DWORD entry, and then click Rename.
Right-click the MapiHttpDisabled entry, and then click Modify.
The Edit DWORD Value dialog box appears.
In the Value box, type 00000001, and then click OK.
Close the Registry Editor.
Verify that the protocol has been changed to RPC over HTTP.
Restart Microsoft Outlook.
Press Ctrl and right-click the Microsoft Outlook icon in the notification area at the far right of the task bar.
Click Connection Status.
The Microsoft Exchange Connection Status dialog box appears.
Verify that the value in the Protocol column is RPC/HTTP.
If the value is HTTP, delete the Microsoft Outlook profile, and then recreate it.
3. Double open the MAPIoverhttp_disable.reg file and it will add the above change for your.
Disabling MAPI over HTTP using Command Prompt.
1. Click Start RUN
2. Type CMD then hit ENTER.
3. Type or paste: REG.exe Add HKCU\Software\Microsoft\Exchange /V MapiHttpDisabled /T REG_DWORD /D 0x1 /F (Note that the above is one line that may wrap)
Disabling MAPI over HTTP using PowerShaell
We can retrieve the current configuration using the first two commands, whilst the third one disables MAPI/HTTP and the final command enables MAPI/HTTP: Get-Item HKCU:\Software\Microsoft\Exchange Get-ItemProperty -Path HKCU:\Software\Microsoft\Exchange -Name MapiHttpDisabled | select MapiHttpDisabled | Ft –AutoSize New-ItemProperty -Path HKCU:\Software\Microsoft\Exchange -Name MapiHttpDisabled -PropertyType DWORD -Value “0x1” –Force New-ItemProperty -Path HKCU:\Software\Microsoft\Exchange -Name MapiHttpDisabled -PropertyType DWORD -Value “0x0” –Force (Note that the above are all one line that may wrap)
Testing When MAPI/HTTP Disabled
For reference, Outlook 2010 connection information is show. Note that MAPI/HTTP is being used:
After disabling MAPI/HTTP using one of the above methods, reg.exe or PowerShell, we can then look to see how Outlook is connecting. Note that you may have to wait for Outlook to perform an Autodiscover request and automatically update itself, or alternatively run a profile repair to force a full Autodiscover. Deleting the Outlook profile would also force the change, but that is not recommend in production unless it is the last resort. Deleting Outlook profiles causes OAB downloads, OST downloads, possibly adding PST files back into the profile and may also impact mobile devices.
In the below screenshot we can se that the client is now kicking it old skool. The protocol type has changed, and there is now a proxy server specified. This was taken after restarting Outlook.
Enabling Via Command Prompt
To allow MAPI/HTTP remove the MapiHttpDisabled DWORD, or set it to a value of 0 as shown below: