Surprise surprise 3rd party (and the usual suspects at that) AV software causing problems with Windows Update!

Replying to my own post
The problem is only with the following products - not the personal user
http://forum.kaspersky.com/index.php?showtopic=261559

Kaspersky Lab informs you that upon installing Microsoft KB2823324 update (dated 08.04.2013) on the following operating systems:

Microsoft Windows Vista x32/x64,
Microsoft Windows 7 x32/x64,
Microsoft Windows Server 2008 x32/x64,
Microsoft Windows Server 2008 R2

the following situations may happen:

1. Kaspersky Anti-Virus for Windows Workstations / Server version 6.0.4.1424 and 6.0.4.1611 displays the message: "Your license is not valid. Protection disabled." As a result, some or all protection components stop functioning.

2. the chkdsk utility is launched on a computer with Kaspersky Anti-Virus for Windows Workstations / Server version 6.0.4.1424, 6.0.4.1611 or Kaspersky Endpoint Security 8 for Windows version 8.1.0.831 each time the operating system is started.

Seems they're more trouble than they're worth at times 3rd party AV programs

In reply to a post by bobble_bob:

Seems they're more trouble than they're worth at times 3rd party AV programs

I think that often depends on the settings, e.g. with Kaspersky one can use application restrictions where for unknown applications they are moved to an untrusted group rather than just using heuristic analysis. This prevents all unknown applications from running which can be a very useful form of protection but sometimes this can cause a headache when trying to install and run some programs.

Obviously trusting digital signatures and not allowing unknown apps to run does not give 100% protection but it is probably better than nothing