I had this same problem, however I uninstalled 360 totally and then reinstalled it from their website. I then installed the FF add-on from the 360 website and it went in flawlessly.. The strange thing is that the revision level went backward (from 1005 to 1004) when I installed the plug in from the 360 website however the update date went forward to July 25 2017 (today) . Hmmm

Complete protection is paramount with online activity.

Cool.

Nice job

Very good

Very easy to get along with this program...

User hk
4 Engine is a really good basis.
viruses and internet is becoming much more dangerous than 20 years before. But in this old time most people was to unserios in handling with computer -may today same (a lot of new technik egg smartphones tabletts...)- every medium must be av-checked, downloads too.......
here 360 helps very much in an easy way, and checking all files (archives too -without limites....)....
performens keeps -in my opinion- very good, i'm using an old system............
thank you 360

Thank you for the sharing this security extention.

Get support

流氓软件，居然到火狐来做虐了！天理何在！

Awesome well thought out. Always learning new things using this.