After latest Windows 10 Update KB4451762 (installed 4/11/20), Firefox can't download any application installer files. Always gives error "download failed".
This just started after Windows 10 update KB4551762 installed. Firefox 75 still browses OK, but will not download any application installer files. Another Firefox-based browser (Palemoon) suddenly has the same problem. Non-Mozilla browsers (Opera/Chrome) continue to download application installers OK from the web. Tried refreshing and reinstalling Firefox 75, but that does not fix the problem. I suspect the Windows 10 update rather than Firefox, because the latest Firefox in a Linux system works OK.
Hi lewishmorgan, Thanks for posting this. I'm sure that Mozilla Support will look into it.
It looks kinda creepy to me: KB4551762 https://support.microsoft.com/en-us/help/4551762/windows-10-update-kb4551762
saying that: "new features will remain dormant until they are turned on using an enablement package"
Anyway, I'm sure that they're working on it
Robertj, Thanks for your reply. I first thought the Windows update KB4551762 might be solely to blame, but now it looks like some updates installed the previous day (4/10/20) might be contributing to or causing it, namely:
KB4540673 (another cumulative update), KB4052623 (Windows Defender), and KB4537572 (.NET Framework).
Firefox was working OK before installing those, but I didn't notice the problem until after KB4551762.
Other peculiarities have shown up: some, but not all, installed apps will no longer start up from the W10 Desktop icons in my primary user account (which has Administrator privileges), but will start from the secondary limited user account (which does not have Administrator privileges). This is opposite to the usual state of affairs.
Likewise, while in my W10 primary user account, downloading from the web via Firefox an application installation file, Firefox will fail (it will not even start downloading), but the download may succeed with Firefox in my limited user account.
So screwy it's hard to believe it's accidental - makes me wonder if someone at MS is doing it deliberately.
JF -- I have been having the same issue now on every system that is running Windows 10 (updated) and Firefox (updated). I am sure that many people have the same issue and would like to find a good resolution for the same.
I have the same issue!! VERY FRUSTRATING that I can not download ANYTHING!! If I can't find a solution, I may have to make some changes....