My settings on Windows Update automatically install critical and recommended updates, but not optional ones. This one didn't autoinstall for me, it was in the queue. Looks like it failed on Jan 29th when a large number of other updates were installed.

I installed it today, and didn't have any problems. Took a few minutes to download, and longer than that to install, but it went through.

Hard to say how important it is, because I don't know what applications I have loaded that may use the dot net features, or how many of those features are used by websites I frequent. I figured it was safer to install it than not, for security reasons.

__________________
2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue