Could you please tell us what the error message says? Thanks.

The error message says : [Exception... "Component returned failure code: 0x804b000a (NS_ERROR_MALFORMED_URI) [nsIWebNavigation.loadURI]" nsresult: "0x804b000a (NS_ERROR_MALFORMED_URI)" location: "JS frame :: chrome://global/content/bindings/browser.xml :: loadURIWithFlags :: line 186" data: no]

The original poster is "Olivier Benet" and then I see a reply from "ailein" are you two the same person? It's important to know, because the two of you may not be having the same problem.

Olivier is my real name and ailein my pseudonym.

Sorry

Mozilla/5.0 (Windows; U; Windows NT 5.1; fr; rv:1.9.2.6) Gecko/20100625 Firefox/3.6.3;MEGAUPLOAD 1.0

You have or had an extension installed (MegaUpload toolbar) that has changed the user agent from Firefox/3.6.6 to Firefox/3.6.3.

You can see the Firefox version at the top and the user agent at bottom of the "Help > About" window (Mac: Firefox > About Mozilla Firefox).

You can check the general.useragent prefs on the about:config page. You can open the about:config page via the location bar, just like you open a website. Filter: general.useragent If general.useragent prefs are bold (user set) then you can right-click that pref and choose Reset.

See Web sites or add-ons incorrectly report incompatible browser and Find what version of Firefox you are using See also http://kb.mozillazine.org/Resetting_your_useragent_string_to_its_compiled-in_default

I am french and I did not understand everything.

My problem is solved.

When Firefox has Started the next day, I did not have this problem.