Nothing in Windows Event Viewer, but the PHP logs did have an error:
[22-Mar-2012 17:21:52] PHP Fatal error: Call to undefined method Arras_Widget_Tag_Cloud::WP_Widget_Tag_Cloud() in C:\inetpub\apevibro.wwwroot\wordpressclassifieds\wp-content\themes\apeclassifieds\library\widgets.php on line 328
I am using a themed named Arras, it seems this may have some sort of conflict with the update. I Googled this error to see what I could find, see this fix https://www.arrastheme.com/forums/topic6442-15-arras-1501-and-wordpress-32.html. This worked for me!
Thanks for the help t-p, you got me going in the right direction. Sometimes I forget that PHP errors don’t show up in event viewer, I’m generally as ASP.net guy. Auto updated no problem after fixing the widgets.php file.