hello Armby, some other affected users tied the issue to the mcafee site advisor extension - please try to disable or remove that in case you have it present.

Disable or remove Add-ons

THANKS .... I deleted "advisor" and it seems to have solved the problem.

Restarting FF "solves" the problem for a few days for me. Disabling any option always seems to work for a while. Then the odd characters come back. ZoneAlarm Extreme Security is not the problem. Disabling other options has not produced anything more conclusive. I have these Add-Ons: Add To Amazon Wish List Dragon Naturally Speaking EverNote Web Clipper McAfee Site Advisor Troubleshooter

The McAfee SiteAdvisor extension has been reported to cause this issue, so you can disable this extension.

• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

See also:

• How to uninstall SiteAdvisor:
  http://service.mcafee.com/faqdocument.aspx?id=TS100162

Disabling a Firefox extension for a very good McAfee SiteAdvisor program is not a long-term solution to this issue! If, in fact, it IS caused by McAfee SiteAdvisor, it is still YOUR extension, and you guys need to find a fix for this already. And don't tell us to notify McAfee -- That's up to you. You are providing the product, and we are your customers.

It is always the responsibility of the developer of an extension to ensure that its extensions keep working in the current release. Developer version are available quite a while in advance (Firefox 39 is currently in alpha stage) and Firefox 37 is scheduled to be released at the end of the month. McAfee should be aware of these issues and should have taken action.

Strange characters (appears Chinese or Japanese... | McAfee Communities:

• https://community.mcafee.com/thread/76071

So contact the extension developer, and advise him/her that hundreds of people are having this issue. I doubt many of us are going to download alpha and beta versions of new Firefoxes, for any reason, let alone JUST to rectify this issue. I agree McAfee should be aware of the issues, but it's not the responsibility of the subset of Firefox/McAfee users to escalate the issue.

It's not McAfee SiteAdvisor in my case. I've disabled it and the stray characters come back. In fact, re-enabling SA "made" the problem go away for a while. I had similar experiences with Flash, Silverlight, Dragon, and Google Update plugins.

Simply restarting Firefox, with no other changes, makes the problem disappear for some period of time for me. That can deceive users to declare one culprit. Do diligent troubleshooting.

I've had McAfee SA running enabled on 2 Win7 systems for over a month with no character appearances.

Birdieguy said

So contact the extension developer, and advise him/her that hundreds of people are having this issue. I doubt many of us are going to download alpha and beta versions of new Firefoxes, for any reason, let alone JUST to rectify this issue. I agree McAfee should be aware of the issues, but it's not the responsibility of the subset of Firefox/McAfee users to escalate the issue.

Pretty much all users here with Moderator tags only (not with Administrator also) are just users with extra responsibility as we are not employed by Mozilla.

Also he was not saying Firefox users should be testing such builds but rather that McAfee can easily get these builds in testing their extension so it works properly when a new Firefox version is released.