Wow, did I try a lot of things to recover my installation of Adobe Reader XI. More specifically I tried:
– uninstall / reinstall
– uninstall, delete all folders from AppData and reinstall
– delete 2 files from Reader folder to get rid of Tools sidebar (that kept loading, never got anywhere and crashed)
– check Windows logs for any errors
– check antivirus logs for any clues
– allow Adobe Reader through Windows Firewall
After trying all these things I finally managed to solve Adobe Reader XI crashing. Solution:
– install Foxit Reader and set as default program for PDF files.
I am sorry if anybody thought this was gonna be a fix for Adobe Reader. I tried, failed and moved on.