Malware can change how browsers work by silently installing extensions on your machine. Extensions can be installed only if they’re hosted on the Chrome Web Store. Windows developer channel users, as well as those on other operating systems, are unaffected. Extensions that were previously installed may be automatically disabled and cannot be re-enabled or re-installed. If you’re a developer and your extension isn’t in the store yet, please submit it today. This is just one more step we are taking to make sure our users can browse safely.”]
Source: https://chrome.googleblog.com/2014/05/protecting-chrome-users-from-malicious.html