Windows 10 / Outlook 2019 problem

[TehDwonz]

So, this is an odd one affecting one of my end-users, and I'm a bit stumped (for now).

 

New PC, Windows 10 Pro 2004 with Office 2019. All assembled and installed by me. Outlook is using G-Suite Sync (Google Apps Sync) to work with company gmail.

Outlook fails to send outgoing email, with an error suggesting that the MAPI to MIME conversion is failing. The standard fix for this is to re-install G-Suite sync and Outlook from scratch, as apparently corruption of the dlls involved is "common" according to M$... Done that, 3 times. Also run SFC and DISM cleanups with no luck.

 

I spent most of Wednesday afternoon talking with a Google engineer trying to make sure it wasn't the Google Sync software causing the issue - it isn't. ie, we used a third party program to attempt MAPI to MIME conversion - so we know 100% that the fault is with Microsoft, either Windows or Office. We kind of knew this already, but needed to confirm it.

 

There are other users with the same software setup and versions having no issues too, which makes it extra annoying.

 

So, do any of you know if there is a way to obliterate and re-install/repair anything relating to MAPI to MIME conversion in Windows 10?

[Radium_Angel]

2 minutes ago, TehDwonz said:

So, this is an odd one affecting one of my end-users, and I'm a bit stumped (for now).

 

New PC, Windows 10 Pro 2004 with Office 2019. All assembled and installed by me. Outlook is using G-Suite Sync (Google Apps Sync) to work with company gmail.

Outlook fails to send outgoing email, with an error suggesting that the MAPI to MIME conversion is failing. The standard fix for this is to re-install G-Suite sync and Outlook from scratch, as apparently corruption of the dlls involved is "common" according to M$... Done that, 3 times. Also run SFC and DISM cleanups with no luck.

 

I spent most of Wednesday afternoon talking with a Google engineer trying to make sure it wasn't the Google Sync software causing the issue - it isn't. ie, we used a third party program to attempt MAPI to MIME conversion - so we know 100% that the fault is with Microsoft, either Windows or Office. We kind of knew this already, but needed to confirm it.

 

There are other users with the same software setup and versions having no issues too, which makes it extra annoying.

 

So, do any of you know if there is a way to obliterate and re-install/repair anything relating to MAPI to MIME conversion in Windows 10?

Make a fresh user account on that PC, see what happens, if anything?

[TehDwonz]

1 hour ago, Radium_Angel said:

Make a fresh user account on that PC, see what happens, if anything?

Yes, sorry did try that.

 

 

[TehDwonz]

Oh thanks Microsoft... turned on extended debug logging, and this appears in the logs:
 

Quote

Security warning loading gsync.dll. This MAPI provider DLL might be harmful to your system. You should only load DLLs from trusted providers that have been registered in MapiSvc.Inf. This provider DLL will be blocked in a future Outlook client update and its functionality will no longer be available. For more information about registering provider DLLs, see https://go.microsoft.com/fwlink/?linkid=2009861&clcid=0x409.

 

They started blocking gsync.dll. 

[Guest]

25 minutes ago, TehDwonz said:

Oh thanks Microsoft... turned on extended debug logging, and this appears in the logs:
 

 

They started blocking gsync.dll. 

That doesn't really surprise me, they do tactics like this all the time utilizing various Windows Services. They have flagged both chrome and firefox in the past as potentially harmful, they flagged fraps for a bit after they added streaming and recording to the xbox game bar, Thunderbird has been flagged in the past after Microsoft Mail became a thing, they tried to say that Anti Malware software was malicious at one point before they started offering better integration with Windows, the list goes on. They have been doing shady things ever since the introduction of Windows 10, if they offer something, they don't want you to use a alternative. Considering the mass adoption of Google Services in schools and slowly making its way into businesses, I am not surprised they want to block Google Mail in outlook.

 

Anyways, you could try using Thunderbird, its more dated looking but I am unfamiliar with a good alternative for Windows.

[Radium_Angel]

4 hours ago, TehDwonz said:

Oh thanks Microsoft... turned on extended debug logging, and this appears in the logs:
 

 

They started blocking gsync.dll. 

Bastards

[TehDwonz]

11 hours ago, Radium_Angel said:

Bastards

Running out of options now - added gsync32.dll to exclusions in Defender (just as an extra), and also added it to the relevant registry entries for Office to allow "unofficial" add-ons etc, using:

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\SOFTWARE\Policies\Microsoft\Office\16.0\Outlook\TrustedProviders]
"gsync32.dll"=""

[HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\Outlook\Security\TrustedProviders]
"gsync32.dll"=""

Still being blocked on some level. If I find a solid solution I'll post it here. Going on-site shortly to attack it with a hammer...

[Radium_Angel]

22 minutes ago, TehDwonz said:

Running out of options now - added gsync32.dll to exclusions in Defender (just as an extra), and also added it to the relevant registry entries for Office to allow "unofficial" add-ons etc, using:

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\SOFTWARE\Policies\Microsoft\Office\16.0\Outlook\TrustedProviders]
"gsync32.dll"=""

[HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\Outlook\Security\TrustedProviders]
"gsync32.dll"=""

Still being blocked on some level. If I find a solid solution I'll post it here. Going on-site shortly to attack it with a hammer...

What are you guys using for a firewall?

[TehDwonz]

4 minutes ago, Radium_Angel said:

What are you guys using for a firewall?

pfsense, custom hardware. Locally on PCs, just Win Defender (and yes, Outlook and related are allowed through). Remember: it's only doing this for one person. At least one other user has a 99% identical system - which is why I am going on-site today when nobody else is there, so I can put them side-by-side and spend [x] hours trawling through them to find that 1% difference...

[Radium_Angel]

12 hours ago, TehDwonz said:

pfsense, custom hardware. Locally on PCs, just Win Defender (and yes, Outlook and related are allowed through). Remember: it's only doing this for one person. At least one other user has a 99% identical system - which is why I am going on-site today when nobody else is there, so I can put them side-by-side and spend [x] hours trawling through them to find that 1% difference...

How did it go?

[TehDwonz]

19 hours ago, Radium_Angel said:

How did it go?

Badly... Removed all traces of Office and gsync from the machine and started again. Same problem with the dll being blocked somehow - even with Outlook in debug mode, it never reveals what is blocking it, and/or why.

Scrapping gsync for this one user and going IMAP with another non-gapps tool, to just sync the contacts and nothing else.

[Radium_Angel]

2 minutes ago, TehDwonz said:

Badly... Removed all traces of Office and gsync from the machine and started again. Same problem with the dll being blocked somehow - even with Outlook in debug mode, it never reveals what is blocking it, and/or why.

Scrapping gsync for this one user and going IMAP with another non-gapps tool, to just sync the contacts and nothing else.

Lovely.

It's probably nothing you have done, MS has a history of "accidentally" blocking gmail, and in turn Google "oopsie!" wiping out MS stuff.

You're just caught in the crossfire

[TehDwonz]

13 hours ago, Radium_Angel said:

Lovely.

It's probably nothing you have done, MS has a history of "accidentally" blocking gmail, and in turn Google "oopsie!" wiping out MS stuff.

You're just caught in the crossfire

Update: it's more fundamental than just gapps/Outlook it seems. Scrapped gapps and went for a manually created IMAP/SMTP option. Guess what? Outgoing gets blocked. It's actually blocking the MIME conversion process that's either built-in to Windows or Office. Genius.
Made a temporary test profile on my own PC with the user's login, all fine.

Now going to resort to the nuclear option and wipe and re-install Windows...

[Radium_Angel]

3 hours ago, TehDwonz said:

re-install Windows...

MS's tag line since it's beginning "If all else fails, nuke and pave"

[TehDwonz]

On 9/7/2020 at 1:24 PM, Radium_Angel said:

MS's tag line since it's beginning "If all else fails, nuke and pave"

Indeed... had to resort to starting from scratch. Did try offline SFC and DISM again, but using an external source WIM, but even that failed to correct the issue (wtf?). Adding this info for anyone finding this thread later on - don't waste your time on this one, just NUKE IT FROM ORBIT and save yourself a day or two...