Crash Sleuthing: Outlook crashes after IE9 install (UPDATE)

As you can imagine, I run a lot of systems here at the PC Doc HQ, and these systems all have a slightly different hardware and software configuration, so when I get a crash on one system I don't expect to see it on all systems. Imagine my surprise when several systems start messing about in exactly the same way.

The problem started a few weeks ago. I installed IE9 onto a system running Outlook 2007 and almost immediately noticed that Outlook started randomly crashing. I half-heatedly carried out some investigation and found that Outlook also crashed when I accessed Trust Center. This wasn't my main system, the logs were of no immediate help and the crash was intermittent enough for me to decide to 'leave the problem for another day.'

Fast forward to today, and two other systems start displaying the problem. The common thread ... IE9 had just been installed.

OK, time to put my deerstalker on and do some sleuthing ...

... well, actually, no, the first thing I decided to do was be lazy. Since Outlook 2007 is now old, and I had enough spare licenses to upgrade to Outlook 2010, I might as well spare myself the headache and just upgrade. Surely that would fix things?

Nope. In fact, the problem seemed much worse, which Outlook crashing on startup.

Drat!

One benefit of upgrading Outlook to 2010 is that I could now access the COM add-ins without Trust Center crashing or having to dig in the registry and disable ... well, pretty much everything ...

... which didn't help ...

Hmmm, looks like I was going to have to do some sleuthing after all.

OK, so now I have one machine running Outlook 2010 and two other machines running Outlook 2007 where Outlook is crashing, all three after IE9 was installed. Even starting Outlook in safe mode (using the outlook /safe switch) didn't make Trust Center behave.

While all three machines are different, they also share a number of similarities in terms of antivirus, add-ins and applications. But the commonality in all three crashes was the installation of IE9 ... and that all three installs were Vista (two 32-bit, one 64-bit).

So to test I uninstalled IE9 off one system ... and Outlook 2010 starts behaving itself. The I did the same on another system ... and Outlook 2007 starts behaving itself.

Now, I'm not ready to call this an IE9 problem just yet as I have more investigating to do, but IE9 is certainly a trigger. A search of 'the Internet' for others with the problem turns up zilch (that's on any use anyway), so it's not a common problem. But then three systems affected by exactly the same problem certainly doesn't exactly scream rare occurrence either.

I'm not done with this problem yet, but for now my only salvation is to uninstall IE9 and see if I can replicate/duplicate the problem on another system.

Stay tuned!

[UPDATE: We're still working away on this issue along with some folks from Microsoft. One thing we've managed to rule out is the involvement of security software in the matter (which some people had suggested might have played a part in the problem.]

PS: Anyone else seen something similar? Let me know!