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When I start Firefox, I get this alert message "[JavaScript Application] XML tag name mismatch (expected META)". What is this message?

kproctor561
kproctor561
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My firefox updated today automatically, and then when it started up, it displayed this alert message:

"[JavaScript Application] XML tag name mismatch (expected META)"

I can press OK and my browser then works just fine and I can go to websites and what-not. I have not run across any problems or anything. I am just wondering what this alert message means and if I should fix it?

I tried closing the browser and pulling it back up, and the same message was displayed. Also, if I open a new window the same message is displayed. But it is only displayed right when I open the browser, and does not show up anytime while using the browser.

My firefox updated today automatically, and then when it started up, it displayed this alert message: "[JavaScript Application] XML tag name mismatch (expected META)" I can press OK and my browser then works just fine and I can go to websites and what-not. I have not run across any problems or anything. I am just wondering what this alert message means and if I should fix it? I tried closing the browser and pulling it back up, and the same message was displayed. Also, if I open a new window the same message is displayed. But it is only displayed right when I open the browser, and does not show up anytime while using the browser.

All Replies (1)

jscher2000 - Support Volunteer
jscher2000 - Support Volunteer
  • Top 25 Contributor
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If you click the Home button from another page, does the error repeat? If so, what is your home page?

When Firefox starts, it fires up a lot of add-ons. A standard diagnostic for add-on issues is to try Firefox's Safe Mode.

First, I recommend backing up your Firefox settings in case something goes wrong. See Back up and restore information in Firefox profiles. (You can copy your entire Firefox profile folder somewhere outside of the Mozilla folder.)

Next, restart Firefox in Firefox's Safe Mode (Diagnose Firefox issues using Troubleshoot Mode) using

Help > Restart with Add-ons Disabled

In the Safe Mode dialog, do not check any boxes, just click "Continue in Safe Mode."

Do you still get the message? If not, one of your add-ons might not be fully compatible with Firefox 14 or might need an update.