The Short Version (30 seconds)
This error shows up when something—usually a browser extension—blocks JavaScript from using eval(). Google Search legitimately uses eval for some dynamic content loading. A security tool or ad blocker is stepping on it.
First try: Open a private/incognito window. Load Google and search something. If the error's gone, it's an extension. If not, skip to the moderate fix below.
Had a client last month whose IT department pushed a 'security' extension. Took me 30 seconds to find by opening a private window. They thought their browser was broken. Nope.
The Moderate Fix (5 minutes)
Private window worked? Good. Now we hunt the culprit.
Disable extensions one by one
- Open Chrome menu → More Tools → Extensions (or
chrome://extensions) - Toggle each extension off, then test Google Search
- Common offenders: ad blockers (uBlock Origin, AdBlock Plus), privacy tools (Privacy Badger, Ghostery), and script blockers (NoScript, ScriptSafe)
In Firefox, go to about:addons and do the same. I've seen uBlock Origin's "advanced user mode" block eval even on trusted sites. If you find the culprit, either disable it on Google or adjust its settings.
Check for malware extensions
Sometimes a shady extension slips in. Look for anything you don't recognize. I had a client whose browser had three 'Weather' extensions from unknown publishers. One was injecting ads and blocking eval. Remove anything suspicious.
The Advanced Fix (15+ minutes)
Still seeing the error in a clean browser window? Or you're not using any extensions? Then something else is modifying your browser's security settings or network traffic.
Reset Chrome flags
If you've messed with chrome://flags, some experimental features can break eval. Hit chrome://flags, click "Reset all to default", restart the browser. This is rare but I've seen it twice.
Check group policies (Windows/Mac)
Corporate machines often have enforced security policies that block eval. On Windows, open gpedit.msc and look under Computer Configuration → Administrative Templates → Google Chrome → Content Settings. If "Disable JavaScript" or "Block eval" is enabled, you need IT to change it.
On Mac, check /Library/Managed Preferences/com.google.Chrome.plist. If you see JavaScriptAllowed set to false, that's your problem.
DNS or proxy interference
Rare, but some corporate proxies or DNS filters inject headers that tighten CSP (Content Security Policy). Open Developer Tools → Network tab, reload Google Search, and look at the response headers. If you see Content-Security-Policy: script-src 'self' without 'unsafe-eval', that's blocking eval.
Test by temporarily bypassing the proxy (if allowed). Alternatively, use a VPN to bypass DNS-level filtering. I had a client in a shared office where the landlord's router injected CSP headers. We swapped DNS to Cloudflare and it fixed everything.
Malware scanning
If none of this works, run a full malware scan. There's malware that manipulates browser settings at the system level. Use Malwarebytes or Windows Defender offline scan. I've seen a browser hijacker that blocked eval to force users onto their ad-filled search result pages.
When to ignore the error
If Google Search works fine and the error only shows in the console (F12), you can safely ignore it. It's a warning, not a show-stopper. But if pages load slowly or parts of Google are broken (like autocomplete), fix it.
One last thing: if you're a developer and you see this on your own site, you need to add 'unsafe-eval' to your CSP's script-src directive. But for Google Search, that's not your problem.