This Firefox-specific error occurred when external origin requests were blocked by browser extensions or network interference. The error was common in older versions of Firefox (until around 2019) when ad blockers, antivirus software, or CORS misconfigurations prevented external requests from completing.
The error manifested in two distinct variants depending on how the blocked request was initiated, both involving Firefox’s internal nsresult error codes.
Note: This error primarily affected older Firefox versions and is rarely encountered in modern Firefox installations.
The Problem
“nsresult: 0x805e0006” was a Firefox-specific error that occurred when external origin requests were blocked by browser extensions, antivirus software, or CORS policy violations. The error presented in two different formats:
XMLHttpRequest variant:
Exception "<no message>"
nsresult: "0x805e0006 (<unknown>)"
Location assignment variant:
Component returned failure code
nsresult: "0x805e0006 [nsIDOMLocation.replace]"
The first variant was triggered when making requests through XMLHttpRequest and thrown when invoking send() or emitted via addEventListener. The second occurred when assigning new locations to window.location or creating iframes.
Key point: This error indicated that Firefox detected and blocked a request due to extension interference or security policy violations, not issues with your application code.
Understanding the Root Cause
“nsresult: 0x805e0006” originated from several sources of request blocking in older Firefox versions:
1. Browser Extension Interference
Most common cause: Extensions like AdBlock Plus, McAfee Antivirus, and other privacy/security tools blocked external requests they deemed suspicious or unwanted.
How to identify: Errors occurred primarily for users with ad blockers or security extensions installed.
2. CORS Policy Violations
Cross-origin requests without proper CORS headers were blocked by Firefox’s security policies, resulting in nsresult errors.
How to identify: Errors occurred when making requests to different domains without server-side CORS configuration.
3. Corporate Proxy Interference
Network-level filtering and corporate proxies modified or blocked requests, causing Firefox to report nsresult errors.
How to identify: Errors were more common in enterprise environments with network filtering.
4. Antivirus Software Blocking
Security software like McAfee intercepted and blocked network requests they considered potentially malicious.
How to identify: Errors correlated with specific antivirus software installations.
How to Fix nsresult: 0x805e0006
Quick Troubleshooting Checklist
- Recognize this as extension/network interference, not application bugs
- Wrap risky external requests in try/catch blocks
- Configure error monitoring to ignore nsresult errors
- Test application functionality with ad blockers enabled
- Ensure core features work when external requests are blocked
Since this error was caused by client configuration rather than code issues, the focus was on defensive programming:
Step 1: Implement Defensive Error Handling
Wrap external requests and potentially blocked operations in try/catch blocks:
// Wrap risky external operations
try {
loadMyAdvertiser();
} catch(e) {
// Show alternate content or gracefully degrade
console.log('External content blocked, showing fallback');
showAlternateContent();
}
// Handle XMLHttpRequest failures
var xhr = new XMLHttpRequest();
xhr.open('GET', 'https://external-api.com/data');
xhr.addEventListener('error', function(e) {
if (e.target.status === 0) {
console.log('Request likely blocked by extension or network filter');
handleBlockedRequest();
}
});
xhr.send();
// Handle iframe creation failures
try {
var iframe = document.createElement('iframe');
iframe.src = 'https://external-widget.com/embed';
document.body.appendChild(iframe);
} catch(e) {
console.log('Iframe creation blocked, using alternative');
showAlternativeWidget();
}
Step 2: Configure Error Monitoring Filters
Set up ignore rules to filter out nsresult errors since they represented user/network configuration rather than application bugs:
// TrackJS configuration to ignore Firefox nsresult errors
TrackJS.install({
token: 'your-token-here',
onError: function(payload) {
// Filter out Firefox nsresult errors
if (payload.message && payload.message.includes('nsresult: 0x805e0006')) {
console.log('Filtered Firefox nsresult error - extension interference');
return false; // Don't track this error
}
// Filter based on Firefox-specific error patterns
if (payload.message && payload.message.includes('Component returned failure code')) {
return false; // Don't track Firefox component errors
}
return true; // Track other errors normally
}
});
TrackJS Ignore Rule Configuration:
- Message contains:
nsresult: 0x805e0006 - Browser: Firefox
Step 3: Monitor Error Patterns
Track nsresult error frequency to understand the impact of extension blocking on your user base. Error monitoring services like TrackJS helped identify which external integrations were most commonly blocked and whether blocking affected core application functionality.
While these errors should be filtered from alerting, monitoring trends helped understand user environment characteristics.
When to Ignore This Error
“nsresult: 0x805e0006” should almost always be ignored because:
- Client-side configuration: Caused by user extensions or network settings, not application bugs
- Firefox-specific: Only affected older Firefox versions (until ~2019)
- Security by design: Extensions and antivirus software working as intended
- No code fixes available: Cannot prevent user choice to block external requests
However, investigate if:
- Core functionality breaks: Essential features fail when external requests are blocked
- High user impact: Large percentage of users affected by blocking
- CORS misconfiguration: Server-side CORS setup needs correction
Summary
“nsresult: 0x805e0006” was a Firefox-specific error from older browser versions (until around 2019) that occurred when extensions, antivirus software, or network policies blocked external requests. This error represented client-side interference rather than application bugs.
The appropriate response was implementing defensive error handling with try/catch blocks around external operations and filtering these errors from monitoring systems. Applications needed to gracefully degrade when external resources were blocked while maintaining core functionality.
Remember: This error indicated security and privacy tools working correctly to protect users. The focus should be on ensuring your application works well even when external dependencies are blocked.
