Starting Firefox 100, Windows 7 SP1 users must have installed the KB4474419 update to install Firefox, otherwise, its installation may fail. This is because Mozilla has signed Firefox for Windows installer with a SHA-256 digest than SHA-1.
Firefox 100
Some Windows Updates, especially Security updates are pretty mandatory. If users don’t install them on their device Windows may not work properly and you can’t install certain apps also. Such is the case with Firefox 100 release on Legacy Windows OS.
Back in 2019, Microsoft ditched Sha-1 and introduced SHA2- code signing support for Windows 7 SP1 and Windows Server 2008 R2 SP1, and Windows Server 2008 SP2 with KB4474419.
You may have the update automatically installed by now.
If you don’t have the mandatory update installed, Firefox installation may fail and you could receive errors like the below or another:
“The operating system does not support the SHA-2 as the signature algorithm. To install the application, you must install Windows Security update KB4474419.”
Firefox installer for Windows comes signed with SHA2-digest
“Beginning in this release, the Firefox installer for Windows is signed with an SHA-256 digest, rather than SHA-1. Update KB4474419 is required for successful installation on a computer running the Microsoft Windows 7 Operating system” Mozilla noted.
You can install this update on Windows 7 SP1 via Windows Update or from the Micorsoft update catalog.
How to install KB4474419 manually in Windows 7
- Visit Microsoft update catalog
- Select the x86 or x64 version of OS Windows 7 and click the download button
- proceed with update installation.
- After the update is installed, restart the computer and install Firefox again.
Firefox doesn’t support Windows Vista anyway. This change doesn’t affect Firefox running on Windows 8, Windows 10, and Windows 11.
Firefox 100 is scheduled to release on May 03.
With the user agent string hitting a three-digit number, some websites may not work in this version
Are you still using Firefox on Windows 7? Why haven’t you upgraded to Windows 10 or Windows 11? Let us know in the comments below.
More on Firefox:
Firefox 98 arriving today: here is what’s new, changed, and Fixed
Firefox Picture-in-Picture gets YouTube Subtitles and Captions Support
How to restore download Prompt in Firefox 98
Mozilla Firefox gets Windows 11 Style Scrollbars
