This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Avatar for Username

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Lolu chungechunge lwabekwa kunqolobane. Uyacelwa ubuze umbuzo omusha uma udinga usizo.

I keep getting this error message and Firefox won't start....Exc in ev handl: Error: Error setting property on NPObject!

jch3113
jch3113
more options

Firefox won't start and this message keeps coming up....I uninstalled and reinstalled....but didn't help...

Exc in ev handl: Error: Error setting property on NPObject!

Firefox won't start and this message keeps coming up....I uninstalled and reinstalled....but didn't help... Exc in ev handl: Error: Error setting property on NPObject!

Isisombululo esikhethiwe

Disable "McAfee Site Advisor" extension which was just updated to 3.4.0, which probably took it out of the addons block list.

  • "Ctrl+Shift+A" > find McAfee Site Advisor and use "Disable", and then restart Firefox.
  • Do a Google Search no problem
  • It seems that if you re-enable Site Advisor again, and restart Firefox you are okay. At least you know where to look if you get the error again or Google searches slow down.
Funda le mpendulo ngokuhambisana nalesi sihloko 👍 5

All Replies (1)

David McRitchie
David McRitchie
more options

Isisombululo Esikhethiwe

Disable "McAfee Site Advisor" extension which was just updated to 3.4.0, which probably took it out of the addons block list.

  • "Ctrl+Shift+A" > find McAfee Site Advisor and use "Disable", and then restart Firefox.
  • Do a Google Search no problem
  • It seems that if you re-enable Site Advisor again, and restart Firefox you are okay. At least you know where to look if you get the error again or Google searches slow down.