Before starting installation disable your virus protection

[#1]

The above message appears when installing a fair amount of software. What seems to be odd is that the same software often equires a working internet connection to be able to install leaving the system open to infection
I have never disabled my virus protection before installation and never will and haven't noticed any issues with the installed software.
Anyone know the reasoning for requesting the diisbling of protection?    My thoughts are that the developers could possibly decline support is you haven't done so (and you tell them).

[#2]

It rather depends how the security system is setup
In my case it is ask every time but I am sure that there are others where it will block all or part of the installation without asking specially if it involves system protected files or registry keys

[#3]

The reasoning is that any software attempting to install itself on your computer attracts the attention of your security software.  I'm sure that the installation routines are tested with common security software in place but it's impossible for the software writer to test their installation routines against all current and future security software.  So they cover themselves by instructing you to disable your security software during the installation.
     

[#4]

It's not just AV programs that can stop an installation, some firewalls can also interfere as well. I have had issues with AVG, Avast, Avira & Norton anti-virus programs as well as ZoneAlarm, PC tools & Norton firewalls when installing software in the past. In some cases the programs appear to have installed properly but I found certain features did not work or produced strange activity.
It's certainly not as bad as it was but I still get the occasional issue.

[#5]

I have just installed IE9 into my HP laptop with no difficulty at all but when I tried to instal IE8 into my XP Dell it has not gone well. Both machines have Avast AV, Malwarebytes and Spybot and I did not uninstall them. Could this be my problem? These programs do not have a facility to pause them but only uninstal, which seems a lot of effort.
Everything seemed to go well until I tried to fire IE 8 up. The first page appeared but it did not insert M$ address as the Home one which I expected, just nothing. It sat trying to connect to blank and refused to allow me to do anything about it. Eventually it all crashed to "Not Responding". Before this happened, clicking on to Tools produced the drop-down with most of the headings not available, particularly the Options which would allow me to insert a Home address which left me powerless. I have reinstalled a couple of times without any change of performance. Needless to say that it was a jolly boring time wasted.