How do you remove/uninstall Add-Ins for Visual Studio if they are broken?

For Visual Studio 2015 you have to:

1. Click on Tool -> Extensions and Updates.

2. Be sure that Installed option is selected in left part of the window.

3. Find your addin, select it and click on Uninstall button.

4. Restart Visual Studio.

There are a few helpful articles which may be useful for your particular Add-In:

http://www.mztools.com/articles/2006/mz2006018.aspx

First of all I tried this (which may work for you) How to: Deactivate and Remove an Add-In. Note if you don't know the Namespace or ClassName of the addin, you can find it in the .addin file under FullClassName:

To remove an add-in from the integrated development environment (IDE)

1. Delete the .addin XML registration file for the add-in that you want to remove. The default location is ..\Users\username\ Documents\Visual Studio 2010\Addins\
2. At a Visual Studio command prompt, type devenv /resetaddin Namespace.ClassName, where Namespace is the name of your add-in project and Classname is its class name, for example, devenv /resetaddin MyAddin1.Connect

For me this, although not my exact problem, lead to my resolution, which was simply to run Visual Studio as administrator. Doing this for just one version of Visual Studio solved my problem in that the error message no longer appeared (probably because it was then able to successfully rename as per the original error message).