I've been running into a problem installing 5.1.1727.12. I'm running Windows 2008 Server R2 in some sort of lowered-privledges mode (implemented by the IT department). When I install R# it tells me it succeeded; but when I run VS 2010 there is neither a Resharper menu in the main menu (before or after loading a solution) not a Resharper entry in the Tools/Options tree.
I've also got VS 2008 installed and that integration worked fine.
I've tried repair, full uninstall/reinstall, change install unchecking VS 2010 and change re-checking VS 2010. No order seems to make a difference.
Thanks -- Peter