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 [HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\AutoDiscover] "ExcludeExplicitO365Endpoint"=dword:00000001
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
Disable MAPI over HTTP using .reg file.
1. Download this file: MAPIoverhttp_disable.zip
2. Unzip the file
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-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)