I am having this strange issue with kentico and VS2015. I can attach to process on VS 2012 no problem but i do the same steps on VS 2015 and it will not catch. I only have this issue with Kentico for some reason. all other projects i use are fine.
I assume the same instance with VS 2012 is being used in VS 2015?
Have you tried deleting the .suo hidden file by the solution, in case it's conflicting one with the other?
Is debugging enabled in the web.config? Are you running VS with Admin privileges? When you attach, are you sure your website is running? Are you showing all processes?
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