Things have been going well since the release of ANTS Profiler 4, with most of our time spent planning for the new version of the memory profiler; more recently we’ve also started looking at what we could do with .NET Reflector. The performance profiler was also scheduled to receive a few fixes, along with some minor enhancements that we couldn't quite squeeze in for 4.0.

However, last week we had a real "oh no" moment, and as sometimes happens in life, events have overtaken us and forced us to push out a 4.1 release much earlier than we’d planned.

I’ve posted a short announcement here at http://www.red-gate.com/messageboard/viewtopic.php?t=7932, but I wanted to use my blog to go into a little more detail about what happened.

Within the past couple of weeks we’ve had two separate reports of the ANTS Profiler uninstaller causing systems to enter an infinite reboot cycle after a restart. As bizarre as this seemed, we felt compelled to investigate. After some effort we managed to reproduce the problem on Windows Server 2003, and later, on Windows Vista and XP64. We haven't managed to reproduce it on any other OS versions, but since it's such a rare problem, we can't rule out the possibility that they might also be affected.

What's happening is that the uninstaller doesn't unregister one of the services correctly. On a small number of machines—and it’s still not clear why this happens—this causes the infinite reboot cycle.

Fortunately help is at hand...

In the unlikely event that you are affected by this, there are two possible fixes:

• Reboot into the last known good configuration using the F8 startup menu, and manually remove the service using sc delete "ANTS Memory Profiler 4 Service".
• Boot from a Gnoppix CD (or similar)and manually remove the service registration by editing the registry manually—I'd avoid this and go with the first option unless you're particularly confident about messing with the registry though.

If you're at all unsure about doing this, please contact support@red-gate.com, and they'll walk you through it in detail.

Most of you will never see this problem however, to be safe, I'd recommend in the strongest possible terms that you upgrade to 4.1 now. You don't need to uninstall 4.0 first, you can just install the update over the top. The update can be downloaded from

http://www.red-gate.com/products/ants_profiler/index.htm

It's free for anyone who has already purchased ANTS Profiler 4.0.

I’d like to apologise for any inconvenience this causes. It’s the kind of bug that keeps people like me awake at night: a nightmare combination of the catastrophic and the hard to reproduce, which can sneak entirely unnnoticed through your testing process before biting you in the backside at some undefined point in the future… which is exactly what's happened here.

Anyway, the bottom line is it’s potentially serious, but there’s no need to panic, and installing the update will ensure that you don't fall foul of this problem.