This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Avatar for Username

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Èròjà atẹ̀lélànà yii ni a ti fi pamọ́ fọ́jọ́ pípẹ́. Jọ̀wọ́ béèrè ìbéèrè titun bí o bá nílò ìrànwọ́.

problems opening firefox after updating windows 10 with (KB5035845) and 10.0.19041.4163

  • 3 àwọn èsì
  • 0 ní àwọn ìṣòro yìí
  • 7 views
  • Èsì tí ó kẹ́hìn lọ́wọ́ zeroknight

engnrman
engnrman
more options

Windows Updates (KB5035845) and 10.0.19041.4163

After these latest updates, EVERY, Firefox browser (derivatives included, i.e. LibreWolf, etc...) are opening VERY slowly. Its almost like the browser is freezing while opening for around 10 - 20 sec, then opening. It used to open within a second or two. If I uninstall the updates the problem goes away, BUT, windows re-installs them automatically. After it is up and running its ok. The problem seems to be on startup only.

Windows Updates (KB5035845) and 10.0.19041.4163 After these latest updates, EVERY, Firefox browser (derivatives included, i.e. LibreWolf, etc...) are opening VERY slowly. Its almost like the browser is freezing while opening for around 10 - 20 sec, then opening. It used to open within a second or two. If I uninstall the updates the problem goes away, BUT, windows re-installs them automatically. After it is up and running its ok. The problem seems to be on startup only.

All Replies (3)

zeroknight
zeroknight
more options
  • Click the "Clear startup cache" button in about:support.
  • Reset fonts to default in Windows Control Panel > Appearance and Personalization > Fonts > Font Settings > Restore default font settings.
  • Set MOZ_PROFILER_STARTUP=1 environment variable to capture a startup performance profile.
engnrman
engnrman Ìbéèrè olóhun
more options

none of that helped. After I deleted the cache it actually started even slower. It does start instantly when I check troubleshoot mode though. I have no extensions or themes that cause it. I disabled the default, which is all I had installed, and it still happens on restart.

Ti ṣàtúnṣe nípa engnrman

zeroknight
zeroknight
more options

The first start after clearing the startup cache is expected to be slower but subsequent starts should be faster.

engnrman said
It does start instantly when I check troubleshoot mode

Does it still happen if you disable hardware acceleration?

Try changing gfx.e10s.font-list.shared and gfx.font-list-omt.enabled to false in about:config.