similar issue here

also worth noting that manually downloading the firefox installer and using it to upgrade works fine.

Firefox comes in three or more folders on all computers. They are;

Maintenance: (Programs Folder) <Windows Only> Firefox itself: (Programs Folder)

The maintenance program may also need access.

Set the firewall options to alert you when a program wants access.

Separate Security Issue: Update your Flash Player or remove it using these links; Uninstall Flash Player | Windows {web link} Uninstall Flash Player | Mac {web link}

Note: Windows users should download the ActiveX for Internet Explorer. and the plugin for Plugin-based browsers (like Firefox).

Note: Windows 8 and Windows 10 have built-in flash players and Adobe will cause a conflict. Install the plugin only. Not the ActiveX.

Flash Player Version 32.0.0.223

https://get.adobe.com/flashplayer/ Direct link scans current system and browser Note: Other software is offered in the download. <Windows Only>

https://get.adobe.com/flashplayer/otherversions/ Step 1: Select Operating System Step 2: Select A Version (Firefox, Win IE . . . .) Note: Other software is offered in the download. <Windows Only> +++++++++++++++++++ See if there are updates for your graphics drivers https://support.mozilla.org/en-US/kb/upgrade-graphics-drivers-use-hardware-acceleration

thanks for the ideas.

i forgot to mention i had already unblocked the mozilla maintenance service, which has its executable located at: "%programfiles(x86)%\mozilla maintenance service\maintenanceservice.exe"

blocking/unblocking the mozilla maintenance service does not appear to affect the issue.

regarding the mozilla maintenance service, i should mention that it fails to start when i try to start it manually. the error message is "error 1: incorrect function". i doubt this is the cause though because firefox is able to update itself if i disable the outbound firewall.

displaying firewall notifications is only available for inbound connection blocks, as far as i can tell. i can, however, see each time an executable is blocked when attempting an outbound connection. this is visible in the windows security log as an event. over a 24-hour period, there are blocked executables, but none of them are in a folder related to mozilla or firefox. below is a list of the blocked programs:

1. \device\harddiskvolume2\programdata\battle.net\agent\agent.6776\agent.exe
2. \device\harddiskvolume2\windows\system32\svchost.exe
3. \device\harddiskvolume2\windows\system32\lsass.exe
4. \device\harddiskvolume2\windows\system32\wsqmcons.exe
5. \device\harddiskvolume2\program files\malwarebytes\anti-malware\mbamtray.exe
6. \device\harddiskvolume2\program files (x86)\battle.net\battle.net.11346\systemsurvey.exe

the only one of these that firefox could be dependent on for outbound internet traffic is svchost. it's possible that firefox is using a service in an svchost process which is attempting to make outbound internet connections. i'm hoping someone can confirm or deny this.

also worth mentioning is that a manual firefox update is able to successfully determine if firefox is up to date. after updating firefox manually, clicking help => about firefox shows "firefox is up to date". when firefox is not up to date, the updater only gets stuck on the "downloading" part.

Let’s do a full clean re-install;

Note: Firefox comes in three or more folders on all computers. They are;

Maintenance: (Programs Folder) <Windows Only> Firefox itself: (Programs Folder) And two folders in the profile of each user on the computer for each Firefox profile for that user.

If you remove the Firefox folder, the user profiles would not be affected.

Download Firefox For All languages And Systems {web link}

Save the file. Then Close Firefox.

Using your file browser, open the Programs Folder on your computer.

Windows: C:\Program Files C:\Program Files (x86) Note: Check Both Folders

Mac: Open the "Applications" folder. https://support.mozilla.org/en-US/kb/how-download-and-install-firefox-mac

Linux: Check your user manual. If you installed Firefox with the distro-based package manager, you should use the same way to uninstall it. See Install Firefox on Linux; https://support.mozilla.org/en-US/kb/install-firefox-linux

If you downloaded and installed the binary package from the Firefox download page, simply remove the folder Firefox in your home directory. http://www.mozilla.org/firefox#desktop ++++++++++++++++++++++++++++ Look for, and remove any Mozilla or Firefox program folders. Do not remove the Mozilla Thunderbird folder if there is one.

Do Not remove any profile folders.

After rebooting the computer, run a registry scanner if you have one. Then run the installer. +++++++++++++++++++++++++++ If there is a problem, start your Computer in safe mode and try again.

http://encyclopedia2.thefreedictionary.com/Linux+Safe+Mode This shows how to Start all Computers in Safe Mode; Free Online Encyclopedia