Hi, 56.0 works for me on Win7 Home Premium.

Try disabling Norton Security Toolbar - Add-ons Manager (Ctrl+Shift+A) > Extensions.

If that doesn't help, try performing a Clean reinstall. This means you remove your Firefox program files and then reinstall Firefox. This process does not remove your Firefox profile data (such as bookmarks and passwords), since that information is stored in a different location.

To do a clean reinstall of Firefox, please follow these steps: Note: You might want to print these steps or view them in another browser.

1. Download the latest Desktop version of Firefox from mozilla.org (or choose the download for your operating system and language from this page) and save the setup file to your computer.
2. After the download finishes, close all Firefox windows (or open the Firefox menu and click the close button ).
3. Delete the Firefox installation folder, which is located in one of these locations, by default:
   • Windows:
     • C:\Program Files\Mozilla Firefox
     • C:\Program Files (x86)\Mozilla Firefox
   • Mac: Delete Firefox from the Applications folder.
   • Linux: If you installed Firefox with the distro-based package manager, you should use the same way to uninstall it - see Install Firefox on Linux. If you downloaded and installed the binary package from the Firefox download page, simply remove the folder firefox in your home directory.
4. Now, go ahead and reinstall Firefox:
   1. Double-click the downloaded installation file and go through the steps of the installation wizard.
   2. Once the wizard is finished, choose to directly open Firefox after clicking the Finish button.

More information about reinstalling Firefox can be found here.

WARNING: Do not use a third party uninstaller as part of this process. Doing so could permanently delete your Firefox profile data, including but not limited to, extensions, cache, cookies, bookmarks, personal settings and saved passwords. These cannot be easily recovered unless they have been backed up to an external device! See Back up and restore information in Firefox profiles.

If you still want to, you can control updates from Options > General - Firefox updates.

Please report back to say if this helped you!

Thank you.

thank you for your advice. I have disactivated Norton Tool Bar, but this was of no help. I have not yet disinstalled and reinstalled Firefox, because I do not understand why I would have to do this. I worked with great satisfaction with Firefox since last December and never had any problems with it until this latest update which causes me to set back the laptop HP Pavilion dv7 i7 every day now for the third time to be able to work with it. After installation of latest Update 56.0.1 (20171002220106 x64de) and mozilla maintenance service 56.0.1.6484 the laptop does not start up normally but blocks in a temporary profile which does not allow to consult my files nor to open my e-mail Outlook and any new file would be cancelled when shutting down the laptop. This is not satisfactory and I can only reach into my files by setting back the computer. Also in this profile Firefox does not work and the laptop uses the old Explorer 9 which is totally outdated. The laptop does not accept Explorer 11, therefore we installed Firefox with great success until now. I saw also a message saying Firefox 56.0 installed plugins shockwave Flash 27.0.r0 but dont know wha this means. Maybe you can give me some additional instructions please. Thanks very much Ulrich Siegrist

Maybe I should add one additional comment. When the laptop starts up I am entering Windows 7 with finger print and instead of showing soon afterwards the laptop with access to all files and services, the system says "desktop is being prepared" (Desktop wird vorbereitet) and after a long while we enter this temporary profile which does not show the usual desktop facilities, but a very reduced choice, not even the Outlook for my e-mails and as I said before, Firefox is not activated under this scheme. Is there something in this Firefox Update that blocks normal proceedures? Or what must I activate or disactivate in my laptop? Thank you for your further advice. Best regards Ulrich Siegrist

It's hard to see how a Firefox update could affect the operation of your PC when FF itself isn't running. To check, open the Task Manager (Ctrl+Shift+Esc) > Applications tab, and if Firefox is there, click on End Task. v56.0.1 mainly changes 32-bit Firefox users to 64-bit and there has been a few reports of problems. I however doubt that is the cause, but if you want, you can go back to 32-bit by selecting 'Windows 32-bit' in https://www.mozilla.org/en-US/firefox/all/ You will not be automatically changed back to 64-bit again.

The fact that you say it says 'Desktop is being prepared' strongly suggests that a Windows update(s) was installed at the same time as Firefox's update, and it's that which is causing your issue. If any Windows updates were installed when this started, it might be a good idea to uninstall them - Control Panel > System and security > Windows update > View installed updates. You may be able to get further help with Windows at https://www.sevenforums.com/

Good evening. I have followed all of your instructions and made a clean reinstall of Firefox Update 56.0.1, but that did not solve the problem either. My laptop is a 2011 produced HP Pvailion dv7 Intel Core i7-2630QM with CPU@2.00GHz with 8GB RAM and 64-bit system which works with perfection with Firefox 32-bit under Windows 7 Home Premium. I do not think the problem was created by another Windows update, as all of important and optional Windows Updates are installed on this laptop without ever having had any problem with them. Since we could not solve the problem, we have reinstalled Firefox 32-bit and it works again perfectly. Why my 64-bit laptop does not accept Firefox 64-bit I dont know and dont understand. Before Dec2016 I was using MS Explorer 9 which was totally outdated by then and we tried to replace it by Explorer 11 (probably also 64-bit) which my laptop did not accept either for a reason unknown to me. Therefore we switched to Firefox 32-bit, as Firefox 64-bit was not available in Dec2016 and I was totally happy with it. Could it be that the 2011 technology of 64-bit laptops is no longer compatible with 2017 64-bit browsers? Hard to understand, but it could well be so. At this time, Mozilla is insisting to install the 56.0.1 64-bit again and again and I have to take the router off electricity to be cut off internet access and then forbid automatic Firefox updates before reactivating the router to have peace of mind, otherwise the 56.0.1 64-bit version is downloaded again automatically immediately while the laptop gets started to desk top function. The only trouble is that this way I will be working with an old browser system that will become more and more outdated when no further updates are added to it to protect it. If you can find out how my 64-bit laptop could accept 56.0.1 64-bit from Firefox, this would render me a great service. I am looking forward to your kind advice and thank you beforehand for it. Kindest regards Ulrich Siegrist 25.10.2017 23:25pm

We are getting reports of a number of problems with 64-bit Firefox not starting up (or crashing during startup) on systems that ran 32-bit Firefox well, but your issue is very unusual. You can still install 32-bit Firefox by downloading a full installer. See: How to opt out of 32-bit Firefox migration to 64-bit.