My Internet browser is Firefox 49.0.1 and up to date. It is my default browser.
I have Vivaldi 1.4.589.11 installed but rarely use it.
I have uninstalled Internet Explorer or disabled it.
Periodically something changes my default browser. It's not Vivaldi.
The changing usually happens around the time Microsoft updates are due.
Could it be Microsoft Windows changing the default to IE? If it is, how can I stop it or can I?