We use cookies to provide you with a better experience. If you continue to use this site, we'll assume you're happy with this. Alternatively, click here to find out how to manage these cookies

hide cookie message
2,862 Tutorials

How to fix 'URL not valid' messages

Fix hyperlink security problems

QUESTION When clicking on a hyperlink in Mozilla Firefox I often get a warning that the ‘URL is not valid and cannot be loaded’, even when I know it’s genuine. My PC runs Symantec Norton Internet Security 2010 and a-squared Anti-Malware, but I can’t find any settings to adjust to prevent this happening. Martin Perry

HELPROOM ANSWER You shouldn’t be running both Norton and A-Squared, Martin. Running two security products that provide the same function simultaneously can cause them to clash, producing random behaviour problems.

If you’re unable to uninstall A-Squared using Add/Remove Programs, you may need to boot the PC into Safe mode first.

The error message you’re receiving is likely to be caused by a Firefox browser add-on (although the Google Toolbar is often wrongly blamed). In Firefox go to Tools, Add-ons and disable all entries. If all is well after restarting the browser, enable each add-on in turn to identify the culprit.

See also: How to fix everything: the ultimate guide to fixing technology

Get free tech support 24 hours a day at PC Advisor's Helproom Forum

IDG UK Sites

Windows 9 launch event live: Windows 9 launch live blog - find out first as the new Windows is...

IDG UK Sites

Windows 9 and the death of the OS as a must-have product

IDG UK Sites

Video trends: 4K is here – HDR video, VR and 3D audio is coming

IDG UK Sites

Best iPhone 6, iPhone 6 Plus deals: iPhone 6, iPhone 6 Plus tariffs, contracts and prices UK