Browsers & Accounts · How Browsers Keep You Safe · Lesson 2 of 5

Browser Updates and Restarts

Why a downloaded fix does nothing until the browser restarts.

Downloaded is not the same as installed

You already know your browser patches itself. Here is the catch most people miss. The fix often sits waiting until you restart the browser.

Chrome, Edge and Firefox check for updates on their own, in the background. When one is found, the browser downloads it quietly. But the old version is still the one running. Every open tab is still using the old code, holes and all.

Why? A program can't swap out its own parts while they are in use. It is like changing a car's tires while driving. So the new version loads the next time the browser starts.

That is a problem for people who never close their browser. Many people leave it open for weeks, and just put the laptop to sleep. Sleep is not a restart. The browser picks up right where it was, still on the old version.

Browsers try to nudge you:

• Chrome shows an Update label near the menu button at the top right, and a Relaunch button.
• Edge shows an alert on its menu button and a Restart button in Settings.
• Firefox shows a Restart to update Firefox message.
• Safari updates through the Mac's Software Update, along with macOS or as its own item.

Relaunching is less scary than it sounds. Chrome and Edge reopen your normal tabs when they relaunch. Private windows close, so finish anything in them first. If you are typing in a form, save or submit it first.

A simple habit helps. When you see an update label, relaunch at the next natural pause. And shut down or restart the whole computer now and then, instead of only closing the lid.

Checking your version page

How do you know you are up to date? Each browser has an About page. Opening it checks for updates right then, and shows the version number. A version number is the label for one exact release, a long code made of numbers and dots.

• Chrome: menu, then Help, then About Google Chrome. Or type chrome://settings/help in the address bar.
• Edge: menu, then Help and feedback, then About Microsoft Edge. Or type edge://settings/help.
• Firefox: menu, then Help, then About Firefox.
• Safari: check Software Update in System Settings.

The page should say the browser is up to date. If it shows a Relaunch or Restart button, click it.

Why does this matter so much for browsers? Remember zero-days from the Windows course. A zero-day is a hole attackers use before a fix exists. Browsers are a favorite target, because everyone uses one and it touches every website.

When Google fixes a browser zero-day, its release notes often say Google is aware that an exploit exists in the wild. An exploit is the attack code that uses the hole. "In the wild" means it is being used against real people now. Microsoft usually ships the same fix in Edge soon after, since Edge is built on the same engine as Chrome.

Those fixes come out whenever needed, not only on Patch Tuesday. The time between the fix and your relaunch is the gap attackers hope you leave open.

So when you read news of an urgent browser update, do two things. Open the About page. Then relaunch if it asks.