Outlook addin fired an exception - code OLE ERROR 800 A01 A8

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Outlook addin fired an exception - code OLE ERROR 800 A01 A8
Tim Smet

Posts: 37
Joined: 2015-10-06

We are using the latest beta version of addin express where the error / AV with colors had been fixed i think it was adxvcl-v900-b1651-pre. I just downloaded the latest release (adxvcl-v901-b1655-pre) but i can't say i see many changes except some default value for style that got changed from vsDefault to vsOffice2007Plus so i have my doubts in latest version it's fixed as well, but we are about to release a new version build against this latest version.

Anyway clients have recently begin reporting "XXXaddin fired an exception - code OLE ERROR 800 A01 A8" message poping up when using our outlook addin. It has happened in out look version 2013 15.0.5075.1001 and 15.0.5085.1000 and it has also happend in outlook 2016 versions that got updated. So my guess is they changed something in updates in outlook where addin express has problems with.

The reason i suspect addin express incompatibility is because ALL our code is wrapped in Try / Except statements so no exception escapes to outlook and we also never show any exceptions in a dialog.

It could be there is an unhandled exception somewhere that goes all the way up to outlook itselve and outlook is displaying the message then.

Our code has not changed for months (addin express versions did change but our addin code did not) so it must be related to some office update.

The clients having had the error where never working in outlook itselve when it happend outlook was running in the background while they were working in other programs (from us unrelated to outlook) so it could be it happens when outlook is doing some background tasks and or because of WM Messages send (again). But as i can't reproduce it (again) i have no clue whats causing it.

The dialog looks like this and pressing ok produces a bunch of them more (like 5-6) then the message is gone and everything is normal :
User added an image

The message comes random and not very often but it's becomming anoying for clients when it does happen and we already have 3 offices where they had it happen (3 office so could be multiple computers).

anyone having a similar problem or someone know what this is about / why this is happening all of a sudden ?
Posted 19 Dec, 2018 06:30:17 Top
Andrei Smolin

Add-in Express team

Posts: 17125
Joined: 2006-05-11
Hello Tim,

Tim Smet writes:
ALL our code is wrapped in Try / Except statements

I assume you log such exceptions so that no exception is unnoticed, correct? If so, does your log contains exceptions unexplained?

Tim Smet writes:
i can't say i see many changes

Please see https://www.add-in-express.com/add-in-delphi/history.php

If talking globally, Add-in Express contains only one new *serious* thing: support for multiple DPI in ADXOlForms. In theory, it could influence the issue as well. But it doesn't relate to using the object model while the error you experience seemingly relates to using the object model. We think you need to add more debug messages to your code.

Regards from Belarus (GMT+3),

Andrei Smolin
Add-in Express Team Leader
Posted 21 Dec, 2018 06:02:20 Top
Tim Smet

Posts: 37
Joined: 2015-10-06
Hi Andrei,

Yes we log any exception that happens in our try except statements to a file. But if an exception is trapped in one of our try / except functions it will never display a dialog as such message in the screenshot. Those messages are only displayed if you don't handle the exception, or the exception happens outside a try / except statement and it sipple up all the way into the outlook process and then outlook will show the unhandled exception then as a safety.

The clients are also (from what we know at the moment) never working inside outlook, outlook was sitting in the background. We don't use timers or similar functions in our addin, well basically we only react to things / execute code if they for example press a button in the ribbon or intiate a new email window.

We do have a monitor on items add of sent items folders in every account specified but since the clients were not working in outlook itselve it's kinda weird.

i'll scan for places were we might not have added try / except statements (like for example on enabline / disabling ribbon buttons) and more debugging code to try and catch the related function where the problem happens.

According to this https://stackoverflow.com/questions/2352188/outlook-ole-error-800a01a8-when-closing-it-with-more-than-10-outlook-explorer-win "OLE ERROR 800 A01 A8" means object required so i'll verify if we do something related to inspectors and accessing objects.

We already released new version build agains the latest avaiable addin express version, and as said i was using the beta version before, the one you sended to me a few weeks ago to fix the color item thing. I think it already contained the dpi scaling fixes as we had troubles with that also in a word addin.(i used a diff tool to see the changes done on file compared to that beta version, thats why i did not notice many changes as the beta probably already had some code of that)
Posted 21 Dec, 2018 06:28:14 Top