As part of my effort to dump Google Chrome, I deleted my old Google Chrome profiles so that I could create a new empty one for the sole purpose of working on the few add-ons that I'm already working on. Every time I created a new profile in Chrome, I would get extensions in that profile that I didn't install (a Conduit toolbar and an extension called General Crawler). I looked in the control panel, but no apps referenced these extensions and nothing I uninstalled fixed the problem. After some digging, I found out how this was happening and wanted to share.
Google Chrome supports adding entries in the registry that point to extensions. When a new Chrome user is created, these entries are read and then the extensions are installed, with no way for the user to intervene. In my case, the following keys were in my registry:
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Google\Chrome\Extensions\adejipnaieabipfpgddkkbahfmlkmilg path=>C:\Users\USERNAME\AppData\Local\CRE\adejipnaieabipfpgddkkbahfmlkmilg.crx version=>188.8.131.52 HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Google\Chrome\Extensions\dednnpigldgdbpgcdpfppmlcnnbjciel path=>C:\Users\USERNAME\AppData\Roaming\Media Finder\Extensions\gencrawler_gc.crx version=>2.5 HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Google\Chrome\Extensions\lpmkgpnbiojfaoklbkpfneikocaobfai path=>C:\Users\Mike Kaply\AppData\Roaming\Media Finder\Extensions\mf_plugin_gc.crx version=>1.1.0
To prevent this from happening, remove these registry entries and the corresponding CRX files.
And if you have an app that does this, make sure you remove these entries when you are uninstalled. I'm talking to you, Conduit.
I will confess that when Firefox first decided to block third-party add-ons, I was very vocal about not liking the decision. After experiencing how many apps do this to Firefox and Chrome, though, I have changed my tune and am happy with the decision. It helped that it was easy to change this behavior for enterprises.
Hypocrite alert: Now that I know about this, I'm going to recommend it to any of my clients that need a way to install Chrome extensions outside of the store. As much as I hate it, there's really no other good way to install a Chrome extension.