Installing an MSI on Windows 7 fails after 16th January 2009

I am using Windows 7 Beta on my main PC, whilst trying to install an application today I hit a problem, the installer failed on start-up. Firstly I thought it was a corrupt MSI so I tried another application, but it did the same. When I checked the Windows Application event log I found the following

Faulting application name: msiexec.exe, version: 5.0.7000.0, time stamp: 0x49432105
Faulting module name: ntdll.dll, version: 6.1.7000.0, time stamp: 0x49434898
Exception code: 0xc0000005
Fault offset: 0x00000000000ebbaa
Faulting process id: 0x7dc
Faulting application start time: 0x01c97a77da8e8b3e
Faulting application path: C:WindowsSystem32msiexec.exe
Faulting module path: C:WindowsSYSTEM32ntdll.dll

I next hit the forums and found that I was not alone with this problem, it seemed to start around the 16th of January, some people were putting it down to a corrupt Windows Defender update.

The solution was to use the Control Panel Restore tools to roll back to a restore point before the 16th. As this is a newly installed PC I have installed something most days, so it was easy to find such a restore point and roll back.

Once this was done the MSI, lets us see of the problem re-occurs

Update (day of post): I reran Windows Update and it wanted to install ‘Definition Update for Microsoft Forefront Client Security (Antimalware 1.49.2086.0)’, I let it do this and I can still install MSI, so it seems the rollback is a valid solution

Update 22nd Jan: Here are other reports of the same problem and some reported workaround http://www.neowin.net/news/main/09/01/19/windows-7-beta-testers-find-critical-windows-installer-bug