My guess is that you are probably having the same issue as me. See Unable to download files in Windows 10 when Parental Controls are on for more information.

A fix is supposed to be released soon.

Wesley Branton said

My guess is that you are probably having the same issue as me. See Unable to download files in Windows 10 when Parental Controls are on for more information. A fix is supposed to be released soon.

Parental Controls??? I just looked into it and apparently I was part of a family group? No idea why, but i removed myself. And I am still experiencing the issue.

Windows 10 doesn't seem to remove parental control completely once you remove yourself from the family. Do the following:

1. Press the Windows key and R.
2. Type regedit.
3. Go to Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Parental Controls.

You will probably see a Users folder in there and there will probably be a user listed in there. That's the cause of the problem.

Like I said, there should be a fix in Firefox 69.0.3 very soon. In the meantime, you can rollback to Firefox 69.0.1 and that should fix the problem for you until the permanent solution becomes available.

To follow up, if you update now you should get version 69.0.3, which will fix your problem.

Hope this helps.