If I uninstall McAfee I _do not_ receive the following message - Windows Defender failed to initialze along with the error 0x800106ba. I spent a fair amount of time with this and confirmed, at least on my computer (Vista Home Premium, SP1), that uninstalling McAfee lets Windows Defender run without problems.
Are there known conflicts with Windows Defender and McAfee 9.3 (under Vista)?
Glad you found a fix Dave. I haven't yet got 9.3 but WD works just fine normally in my Vista alongside McAfee SC 9.0.
I'll pass this on to the team for investigation.
By the way you can't "Run as Administrator" in MSCONFIG. Had you tried NOT running it as Administrator? That is its default mode.
Go to Computer\Program Files\Windows Defender\Msascui.exe and right-click/Properties and remove the "Run as Administrator" elevation from the compatibility tab.
It isn't strictly true that WD is duplicated by McAfee as it is anti-spyware and VirusScan bring an anti-virus is limited in that regard, unfortunately. WD also has that very useful Software Explorer under Tools where startup items can also be disabled very handily.
(FYI a feature that has unfortunately been removed in the Windows 7 version).
Well, that suggestion worked! No error messages from Windows Defender (WD) upon opening. I also had to go back to msconfig.exe and check the box for it (since I had deselected it). WD does not automatically show itself in my Vista System Tray but it does once I select it from Start.
Since this problem appeared the same time I moved to Security Center 9.3 perhaps it might be a good idea for the good folks at McAfee to take a closer look at this since I was not the only person to have this ... issue.