I just tried booting win 10 in safe mode and was able to successfully auto-update firefox. It looks like it was something in OS that was blocking update. I would be very grateful for possible location for install logs, maybe I will be able to determine which file/process during update was blocked during normal OS operation and which app could cause it. I do not have many apps in background, just cloud drive sync, gpu temperature monitor and anti-malware which I tried disabling. If not, I will have to wait until 19.03 for next update and I will spend hour or more disabling every service and app during boot step-by-step, until I determine which service or which app blocked update.

When a new major version is released then only a limited audience gets an automatic update during the first week, but updating via "Help -> About Firefox" should work in this case. Note that sometimes updates are halted to investigate for possible issues that are under investigation and a minor update is released to fix this. This is to avoid that too many people experience those issues. Firefox 123.0.1 got released last Tuesday.

• https://www.mozilla.org/en-US/firefox/notes/

See also:

• https://support.mozilla.org/en-US/kb/enable-background-updates-firefox-windows

Problem is not with detecting update availability. My firefox properly detects that there is update and tries to install it. Problem is with installation itself which does not occur. I even did not know that there was update but I noticed that my firefox did not launch after clicking icon on taskbar - this is symptom of update pending which tried to install but failed. I have to try to launch firefox again when that happens.

Unfortunately I was unable to determine cause for this behaviour. I tried disabling all possible non-microsoft services via msconfig but it did not work. I could also try disabling all autorun dlls via autoruns sysinternals tool, but I do not want to bother with re-enabling them again. For now I simply downloaded 342KB firefox installer and I will launch it ever month so it could download and manually install latest firefox.

Note that Firefox 124 has been released today, but you may consider to wait a week in case issues are reported that require a minor dot release.

• https://whattrainisitnow.com/calendar/

What security software do you have?

It is possible that your security software is causing the problem. Try to disable security software temporarily to see if that makes a difference.

I am using emsisoft. I think I managed to resolve issue by complete firefox removal with revo uninstaller, along with removing %localappdata%/mozilla folder. I only left AppData\Roaming\Mozilla folder to keep my bookmarks etc. Then I installed it again with small online Firefox Installer (341KB). It installed 124.0.1 version which recognized my old profile this time and it did not create new default one. Today when I tried to launch browser it automatically updated to 124.0.2! Mozilla maintenance service is also back so it looks like issue is fixed for now. I hope it will not return soon ;)

P.S. For now I will leave active checkbox near option "install updates when firefox is closed" because I worry that removing this checkbox might break something again.