On an effort to keep Chrome extensions secure and to keep users away from malicious code that could hurt their browsing experience, last year Google started blocking installation of extensions that are not from the Web Store. However, this policy did not affect version of Chrome from the developer channels. Today, this is about to change, as the search giant will begin blocking extensions that aren’t install from the Web Store on all version of its web browser.
The company says that the new policy will start with the Windows dev channel, later on Mac will follow, and by July all channels will block side-loading of extensions. This also includes the Canary version of Chrome, but it seems that Google doesn’t have any plans to expand the new policy to the Linux version of the browser.
Furthermore, this policy will not block completely the load of non-Web Store extensions, as there are workarounds on loading Chrome extensions manually while in Developer Mode.
According to Google since it started blocking extensions not being served by the Chrome Web Store, the company has seen a drop of seventy-five present drop in customer support to help uninstalling unwanted extensions.
Source Chromium Blog