Google stopped the sideloading of Chrome extensions for Windows users back in May 2014, and only allowed them to be offered via the official Chrome Web Store. In July, that will be extended to all Windows and Mac users, in both regular and developer channels. Google stated that after Windows users started getting extensions just from the Chrome Web Store, the company saw a 75 percent drop in requests from customers to uninstall unwanted extensions.
Google added:
We originally did not enforce this policy on the Windows developer channel in order to allow developers to opt out. Unfortunately, we've since observed malicious software forcing users into the developer channel in order to install unwanted off-store extensions. Affected users are left with malicious extensions running on a Chrome channel they did not choose. As such, starting today we will begin enforcing this policy on all Windows channels. Mac will soon follow, with enforcement for all channels beginning in July 2015.
Google hopes this new enforcement policy will keep Chrome Windows and Mac users "safe from the reaches of malicious software developers."
Source: Google
