Ironically the update was designed to both fix existing bugs and issues with Windows 10 as well as bring new features to the operating system. You also have to download it because it is a service pack and future updates will require the Anniversary Update as a base.

Microsoft has, via its Answers site, confirmed that it has received what it describes as 'a small number of reports' of freezing - limited, it suggests, to systems with the operating system installed on a solid-state drive (SSD) and a separate drive for applications and data - and is actively investigating the issue.

Anyone whose systems refuse to boot since the update, can roll back the update via the Recovery Console's build-reversion option or by booting into Safe Mode and uninstalling the update via the Settings app.