Win 10 Upon Startup Auto Opens Default Browser to MSN Page

Whenever I login (not switch) to any user that user's default browser auto opens to the MSN page, https://www.msn.com/en-gb/?ocid=wispr&pc=u477 . This is not even the browser's Home page. It isn't just 1 particular browser as for diff users it could be diff browsers if they have diff defaults. So it can't be browsers' settings.

I have already tried :

• Disabling "Use my sign-in info to auto finish setting up my device after an update or restart".
• Already disabled "Auto save my restartable apps when I sign out & restart them after I sign in".
• There is no Startup program in Task Manager related to any browser.
• This happens whether or not a browser is set to reopen its previous tabs when it is next opened (N.B. this is not when the user next logs in).

As far as I noticed this only started today.

How do I stop this happening?

It must be a coincidence but in the same timeframe the Net connectivity of my PC has been playing up. While my router shows it is fully connected to the Net, the PC reports it has No Internet both over Ethernet or WiFi. Yet most Net programs work perfectly happily, e.g. browsers (as witnessed in OP) & email. However a few fail to connect, like M/S Solitaire. Also my online bank, thro' all browsers, keeps erroring with "Bad request: Your browser sent a query this server could not understand.".

The PC has a correct local IP. Mobile phones & other WiFi devices connect OK thro' the router.

I have rebooted PC & router numerous times.

Possibly a virus. Some suggestions here: https://www.makeuseof.com/browser-launches-automatic...

Agree above. Quite probably no coincidence at all. Sounds very much like malware / virus you should investigate.

Despite all the failed reboots yesterday the lengthy overnight reboot of PC cleared both issues.