Flawed Trend Micro antivirus update cripples PCs

In what way does it cripple a PC?
I've use it at home for two years now (I buy it for $5. per license per year via Company/Corporate purchase). I do know that when it's updating a person might as well do just about nothing and forget about getting on the internet until it's done updating/patching.
In our work network we use it - tended by a dedicated Server which is governed by Corporate level Servers. It is mandated that we use Trend Micro but we've had little issue with it.
Are you having problem with home version or the version companies use?

I have 2008 pro and 2008 standard on my computers. I've been using it since 2006. Had to use system restore on one computer but do not know what cause it to crash. I also use Auslogic on both systems. In 2006 it was 4* in all the tech sites. Now it is rated at 2 1/2* but I think it does a good job and if It doesn't cause any problems ( they have already fix it) I don't plan to replace it.

I use Trend Micro Internet Security 2008 and had no problems with that update