Google engineers have added a new feature to the Chrome browser that automatically warns users when browsing settings have been altered by malicious software.

The new protection was unveiled in a blog post published Friday by Linus Upson, Google's vice president of engineering. It is designed to augment a feature introduced in October that allows users to return Chrome settings to a factory-fresh state with the click of a single button.

Malicious code frequently included with screensavers and other free software can surreptitiously make any number of changes to Chrome settings. Injecting ads into webpages and blocking the ability to revert settings to those previously chosen by the user are two of the more common ways unscrupulous developers tamper with browser options. The hijackings were among the top issue users reported in Chrome help forums when the reset button was introduced in October. Upson explained:

Despite this, settings hijacking remains our number one user complaint. To make sure the reset option reaches everyone who might need it, Chrome will be prompting Windows users whose settings appear to have been changed if they’d like to restore their browser settings back to factory default. If you’ve been affected by settings hijacking and would like to restore your settings, just click “Reset” on the prompt below when it appears. Note that this will disable any extensions, apps, and themes you have installed. If you’d like to reactivate any of your extensions after the reset, you can find and re-enable them by looking in the Chrome menu under “More tools > Extensions.” Apps are automatically re-enabled the next time you use them. Some hijackers are especially pernicious and have left behind processes that are meant to undermine user control of settings, so you may find that you’re hijacked again after a short period of time. If that happens you can find additional help uninstalling such programs in the Chrome help forum—and remember even if you don’t see the prompt, you can always restore Chrome to a fresh state by clicking the reset button in your Chrome settings.

It's not immediately clear what effect the new warnings might have on Chrome extensions that have been updated to include adware. As Ars reported last month, some adware developers are buying popular extensions and updating them to inject ads into webpages. As Upson explained, however, users who are in doubt about the integrity or trustworthiness of a previously installed extension can use the reset button to disable extensions and later reactivate them if they're deemed safe.