I have a fresh install of VS2015 on windows 8 and intellisense doesn't work at all (nothing!) in any environment.
I also have VS2013 (with Resharper 8)on the same machine which works fine.
Any ideas before I go through a re-install?
Probably the problem is with ReSharper, I'm running VS2013 and VS2015 on the same machine without any issues.
I would try: In Visual Studio 2015, go to 'Tools | Options | Text Editor | C# | General both "Auto list members" and "Parameter information" should be checked.
If that doesn't work I would try to disable ReSharper in VS2013 and try to get the normal intellisense working. Same procedure as above if ReSharper fails to restore the settings.