One of our customers is getting a MAPI error 3 (log in failed) when trying to email from Print Screen.

It sends the first email of the day with no problem but will not send another one until they reboot (restarting ATE does not work). It doesn't seem to matter whether they send the email or cancel it.

This used to work but they have recently upgraded Office (to 365) and their PCs.

It works here of course.

I have attached a screenshot that I took on my PC and modified because this customer always sends terrible ones!

The surprising element here is not that you get the error, but that it works once. Despite the fact that MAPI is entirely implemented by Microsoft in Windows and thus should be expected to work consistently with Microsoft-produced email agents, each new iteration of Outlook seems to throw a new wrench into it.

I'm also confused by the absence of a number following the "error = " in the message box. (Or is it just being obscured by the "x3")? Having the actual error code would be a good place to start. I'm not running Office 365 on my local machine, but I think Ty does, so perhaps we manage to reproduce it here.

Sorry Jack, the error dialog was identical to this one and does have a "3". I could only emulate a "1" so I had to use that and alter it! The screen shot they sent was about 20 pixels wide.

So MAPI error 3, aka MAPI_E_LOGIN_FAILURE, is supposed to mean:


An Internet search for it turns up lots of people with complaints similar to yours, i.e. that it only occurs on one workstation among dozens, that rebooting may help but only temporarily, etc., etc. I've read through a number of them looking for clues but no magic bullets have popped out. One poster suggested that it had something to do with another application that was also using the MAPI interface (some kind of contention over the use of MAPI32.DLL?). Another suggested that after a bunch of updates the problem cleared itself. One suggested that the problem was only introduced with Outlook 2016, along with this note:



Another suggested that they solved their version of the problem by doing the Repair operation on Microsoft Office from the Control Panel.

I'm not sure how helpful any of that is, but you may be pleased to note that in the course of Ty trying to reproduce it, he hasn't yet gotten a MAPI error, but he's reported all kinds of other problems!

Thanks for looking into it Jack. I suspect it is some horrible interaction (or lack of it) between AD, Windows and Outlook. Since they completely did away with the old connection method to Exchange (as they should have) Outlook seems to get problems like this.