Microsoft Edge’s Enhanced Security mode (also called “security mode”) can slow down browsing and occasionally break websites, but the impact is limited and usually fixable. This article explains exactly how it works, why it causes these issues, and how to adjust it so you get both safety and a smooth browsing experience.
What Is Enhanced Security in Microsoft Edge?
Enhanced Security is a built-in feature in Microsoft Edge that adds an extra layer of protection against online threats like malware, phishing, and drive-by downloads. It works by applying a stricter set of security policies to the websites you visit, especially those you don’t visit often. The feature is off by default for most users, but you can enable it in the browser’s privacy settings.
The core idea is to reduce the attack surface by disabling certain web technologies that are frequently exploited by attackers. This includes things like just-in-time (JIT) JavaScript compilation, which makes websites run faster but can also be a vector for malicious code. By turning off JIT, Edge makes it harder for attackers to execute harmful code, but it also makes some websites slower.
How Enhanced Security Works
When you enable Enhanced Security, Edge applies a set of security mitigations to every site you visit. The most significant change is the disabling of JIT compilation for JavaScript. JavaScript is the programming language that powers most interactive elements on the web, and JIT is a technique that browsers use to run it faster. Without JIT, the browser interprets JavaScript more slowly, which can noticeably slow down complex web apps like Google Docs, Figma, or even heavy news sites.
In addition to JIT, Enhanced Security also:
- Disables certain APIs that are rarely used but can be exploited, such as the
SharedArrayBuffer. - Adds extra checks to prevent malicious code from accessing your system.
- Restricts certain types of content, like ActiveX controls, which are largely obsolete but still present in some legacy sites.
These measures are designed to make it much harder for an attacker to compromise your browser, even if you visit a malicious website. However, the trade-off is that some websites may not work correctly because they rely on the very technologies that are being blocked.
Does It Actually Slow Down Browsing?
Yes, Enhanced Security can slow down browsing, but the effect varies depending on the website and your hardware. For simple sites that use little JavaScript, the slowdown is barely noticeable. For complex web applications that rely heavily on JavaScript and JIT, the slowdown can be significant—sometimes up to 30-50% slower page load times and less responsive interactions.
On modern computers with fast CPUs, the slowdown is less noticeable because the CPU can handle the extra work. On older or lower-powered devices, the impact is more pronounced. If you’re using a laptop with a low-power processor, you might notice that pages take longer to load, and animations or transitions become choppy.
It’s also worth noting that Edge’s Enhanced Security has a “balanced” mode that applies the strictest protections only to sites you haven’t visited before. Sites you visit frequently are automatically added to an allowlist and run without the extra restrictions, which can help mitigate the slowdown for your most-used sites.
Can It Break Websites?
Yes, Enhanced Security can break websites, though it’s not common. The main culprits are sites that rely on JIT compilation or specific APIs that are disabled. For example, some online games, video editors, and even certain banking sites may fail to load or show errors. In some cases, the site may appear to work but certain features, like drag-and-drop or file uploads, may not function correctly.
Here are some examples of issues you might encounter:
- A web-based photo editor that uses canvas elements may not render images properly.
- A site that uses
SharedArrayBufferfor multi-threaded processing, like some data visualization tools, may show a blank page. - Older sites that use ActiveX controls (common in enterprise intranets) may display a warning or fail to load entirely.
If you encounter a broken site, you can usually fix it by adding the site to Edge’s allowlist. This tells Edge to apply the less strict “balanced” protections to that site, which typically restores functionality.
How to Choose the Right Security Level
Edge offers three levels for Enhanced Security: Off, Balanced (default when you enable it), and Strict. Here’s how to choose:
- Off: No extra protection. This is the default setting for most users. It’s fine if you only visit trusted sites and have other security software installed.
- Balanced: Applies strict protections to sites you haven’t visited before, but allows trusted sites to run normally. This is a good middle ground for most users—it protects you from new threats without breaking the sites you use daily.
- Strict: Applies the strictest protections to every site, including ones you visit often. This offers the highest security but increases the chance of breaking sites and slowing down browsing.
To change the setting, go to Settings > Privacy, search, and services > Security and look for the “Enhance your security on the web” section. From there, you can toggle it off or choose between Balanced and Strict. If you choose Balanced or Strict, you can also manage the allowlist of sites that are exempt from the protections.
Common Problems and How to Fix Them
If you’re experiencing slowdowns or broken sites with Enhanced Security enabled, here are some common fixes:
- Add a site to the allowlist: If a specific site is broken, click the shield icon in the address bar, then select “Allow this site.” This will add it to the list of sites that use the less strict protections.
- Switch from Strict to Balanced: If you’re using Strict, try switching to Balanced. This will allow sites you visit frequently to run without the extra restrictions, which often resolves both slowdowns and breakage.
- Disable Enhanced Security for specific sites: In the Security settings, you can manage the “Never use enhanced security for these sites” list. Add the problematic site here to completely disable the feature for it.
- Update Edge: Microsoft regularly updates Edge to fix compatibility issues with Enhanced Security. Make sure you have the latest version installed.
Comparison with Other Browsers’ Security Features
Edge’s Enhanced Security is similar to features in other browsers, but it’s more aggressive. For example, Firefox has a “Strict” tracking protection mode that blocks trackers but doesn’t disable JIT. Chrome has a “Secure DNS” feature and uses Safe Browsing, but it doesn’t have a mode that disables JIT. Safari has “Intelligent Tracking Prevention,” but it also doesn’t disable JIT.
The trade-off is that Edge’s Enhanced Security offers a higher level of protection against zero-day exploits, but it comes at the cost of performance and compatibility. If you’re a security-conscious user who visits many unfamiliar sites, the protection might be worth the occasional slowdown. If you’re a power user who relies on complex web apps, you might prefer to keep it off or use Balanced mode.
Frequently Asked Questions
Will Enhanced Security protect me from phishing attacks?
Enhanced Security adds an extra layer of protection against phishing by blocking malicious scripts and redirects, but it’s not a substitute for a dedicated phishing filter. Edge already has Microsoft Defender SmartScreen built-in, which warns you about known phishing sites. Enhanced Security complements this by making it harder for a phishing site to execute malicious code, but you should still be cautious about clicking links in emails or messages.
Can I use Enhanced Security with extensions?
Yes, you can use extensions, but some may not work correctly because they rely on the same APIs that are disabled. For example, a password manager that uses a script to fill in forms might not work on every site. If you notice an extension misbehaving, try disabling Enhanced Security for that site or adding the extension’s website to the allowlist.
Does Enhanced Security affect downloads?
Yes, Enhanced Security can affect downloads. It may block certain file types that are commonly used to spread malware, such as executable files or scripts. If you’re trying to download a legitimate file and Edge blocks it, you can usually override the block by clicking the download notification and selecting “Keep.” However, be cautious—only do this if you’re sure the file is safe.
Why is my bank’s website not loading with Enhanced Security?
Some banking websites use older web technologies that are disabled by Enhanced Security. This is a known issue, and it’s often resolved by adding the bank’s website to the allowlist. If that doesn’t work, you may need to temporarily disable Enhanced Security to use the site, but make sure you’re on a secure connection and the site is legitimate.
Is there a way to see which sites are blocked?
Yes, when a site is blocked or has issues, Edge will show a warning icon in the address bar. You can click it to see details and choose to allow the site. Additionally, the Security settings page shows a list of sites you’ve added to the allowlist, so you can review and remove them if needed.
Does Enhanced Security slow down all websites equally?
No, the impact varies. Static sites with little JavaScript will barely notice a difference, while dynamic sites that rely heavily on JavaScript will see the most significant slowdown. The type of content, such as videos or animations, also plays a role. In general, the more complex the site, the more noticeable the slowdown.