When I searched just “MZ-Tools” on Google some time ago I noticed one of the first results in the second page: Making MZTools for VBA work on Vista and it was amazing to me that some user went as far as finding a way to make an old version of my MZ-Tools add-in for VBA work on Windows Vista and publish a blog post with screenshots of what you needed to tweak that now seems quite popular. Of course I was aware of this problem and I fixed it some months before, so he could have downloaded a new version. But anyway, this illustrates a point: if you don’t take the proper design decisions, an add-in that worked fine on Windows XP (as long as you were administrator), it may not work on Windows Vista because by default even administrators don’t have administrator rights (which although it’s a culture change is a good thing IMHO). My latest article explains some design decisions that you must take into account for your installer (installation time) and your add-in (run time):

HOWTO: Design a Visual Studio add-in to install and run on Windows Vista
http://www.mztools.com/articles/2008/MZ2008011.aspx