Try the Firefox Safe Mode to see how it works there. The Safe Mode is a troubleshooting mode, which disables most add-ons.

(If you're not using it, switch to the Default theme.)

• You can open the Firefox 4.0+ Safe Mode by holding the Shift key when you use the Firefox desktop or Start menu shortcut.
• Or use the Help menu item and click on the Restart with Add-ons Disabled... menu item while Firefox is running.

Don't select anything right now, just use "'Start in Safe Mode" To exit the Firefox Safe Mode, just close Firefox and wait a few seconds before using the Firefox shortcut (without the Shift key) to open it again. If it is good in the Firefox Safe Mode, your problem is probably caused by an extension, and you need to figure out which one.

Please follow the Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems article for that.

When you figure out what's causing your issues, please let us know. It might help other users who have the same problem.

or

The Reset Firefox feature can fix many issues by restoring Firefox to its factory default state while saving your essential information. Note: This will cause you to lose any Extensions, Open websites, and some Preferences.

To Reset Firefox do the following:

1. Go to Firefox > Help > Troubleshooting Information.
2. Click the "Reset Firefox" button.
3. Firefox will close and reset. After Firefox is done, it will show a window with the information that is imported. Click Finish.
4. Firefox will open with all factory defaults applied.

Further information can be found in the Refresh Firefox - reset add-ons and settings article.

Did this fix your problems? Please report back to us!

I have tried starting in Safe mode, but unfortunately, it didn't help.

I've also tried to reset and still nothing.

• Does the problem happen with another computer ?
• Does the problem happen in a new profile ?
• Does the problem happen when security software is temporarily disabled?
• Does the problem happen in IE as well? If so, it's a problem on the system, not Firefox.

Yes, this happens on every computer in the network running Firefox v.17.

This error doesn't happen in the Internet Explorer.

It's not a security issue - problem started right after updating Firefox from v.16.0.2 to version 17.

I've tried reinstalling it, starting in safe mode, reseting.... but this doesn't help.

It is strictly version 17 issue.

Which error do you get?

Can you attach a screenshot?

• http://en.wikipedia.org/wiki/Screenshot
• https://support.mozilla.org/kb/how-do-i-create-screenshot-my-problem

Use a compressed image type like PNG or JPG to save the screenshot.

First screenshot shows Firefox (v.17) reporting an error after typing 192.168.0.105, which is the IP address of the printer. The second one shows correctly opened interface in the Internet Explorer. Btw, this is how all previous versions of Firefox have opened it.

I installed 17.0.1 update today and now everything is OK. ;-)