[compbio]

This would run afoul of the European 'cookie law' (the name is a bit of a misnomer as it applies to more than just cookies). In short: Microsoft needs express permission to store/modify files on my computer.

It will probably be spun like Windows 10 is a security update to old OS's, but that is simply not sincere. Given the problematic privacy/sharing/phone-home settings on Windows 10 one can hardly call it a security improvement.

  You must tell people if you set cookies, and clearly 
  explain what the cookies do and why. You must also get
  the user’s consent. Consent can be implied, but must be
  knowingly given.

  The same rules also apply if you use any other type of
  technology to store or gain access to information on
  someone’s device.

https://ico.org.uk/for-organisations/guide-to-pecr/cookies-a...

  [Under the cookie law permission is needed to] store 
  or gain access to data on the peripherals of a user 
  through an electronic communication network.

http://www.justitia.nl/cookiewet.html

  Article 5.3) Member States shall ensure that the use 
  of electronic communications networks to store 
  information or to gain access to information stored in
  the terminal equipment of a subscriber or user is only
  allowed on condition that the subscriber or user
  concerned is provided with clear and comprehensive
  information in accordance with Directive 95/46/EC,
  inter alia about the purposes of the processing, and 
  is offered the right to refuse such processing by the
  data controller.

http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:...

[tajen]

The total of fines Microsoft has already faced from the European Commission is €2bn. It's mostly for forgetting to give the browser choice in Vista, if I remember well, after doing it properly in XP, and for not publishing the documentation of an API. On the other hand, given automatic upgrades are now a habit, and given Microsoft's monopoly is on a very narrower market (so, not sure it's a monopoly), I'm not sure they can be pursued, if the story is confirmed. Unless we also pursue Chrome's automatic updates.

[compbio]

Most users will (rightly so) view this as an OS upgrade, not as an update. You already gave MS permission to provide you with security updates. You did not give MS permission to upgrade your OS. I feel the difference is of importance as updates are often necessary, while upgrades are not.

  This update installs the Get Windows 10 app, which
  helps users understand their Windows 10 upgrade options
  and device readiness.

https://support.microsoft.com/en-us/kb/3035583

[Silhouette]

One type of update is fixing a defect in the original product -- closing a security vulnerability that should never have been there, fixing some function that didn't work as advertised because of a bug, that kind of thing.

Another type of update changes to the product in ways that are not necessary for the original product to be used as intended. They may be desirable for the customer and/or the developer, and there's nothing wrong with that. However, from the point of view of things like consumer protection law that says you should get what you paid for and it should work as advertised, these two cases look qualitatively different to me.