After upgrading my WinForms VS2013 project to VS2015, I started seeing the MSB3884 \"Could not find rule set file\" warning.
A Google search turned up one MSDN article,
I spent some time looking at the different solutions proposed here - they each had good elements but each required some adjustments. I found a clean solution to be:
Locate an existing or create a element in the project file that has NO conditions (e.g configuration or platform) i.e that will apply to all configurations on all platforms. To this element add a element specifying the relative path to the "Rule Set" directory from the current dev env directory, e.g:
$(DevEnvDir)\..\..\Team Tools\Static Analysis Tools\Rule Sets