It depends on your computer. Up to 10 minutes but might take more.

If you have problems with updating or with the permissions then easiest is to download the full version and trash the currently installed version to do a clean install of the new version.

Download a new copy of the Firefox program and save the DMG file to the desktop

• Firefox 6.0.x: http://www.mozilla.com/en-US/firefox/all.html

• Trash the current Firefox application to do a clean (re-)install
• Install the new version that you have downloaded

Your profile data is stored elsewhere in the Firefox Profile Folder, so you won't lose your bookmarks and other personal data.

• http://kb.mozillazine.org/Profile_folder_-_Firefox

I went mozzilla website and downloaded from there. It took maybe two minutes. There might be a problem with potential hacking because the mozilla site did not say uploading to server. The upgrade was like past ones. And I found porn related downloads. I know people hack in order to use someone computer as a middle source. The message about the new mozzilla pops up in a large box and "urges" you to accept. If you want the new version go to the website.