Starting today, Microsoft says Internet Explorer 10 will enable Adobe Flash content by default while immersive mode is engaged (i.e. "Metro mode" for IE). The change will be delivered via Microsoft's usual round of "Patch Tuesday" updates for both Windows 8 and Windows RT and should be publicly available by the time you read this.

Desktop-only IE10 users are not affected by this update as Flash has always worked fully in desktop mode, just as it does in Windows 7. However, for anyone who spends time in the Metro Start Screen and uses the touch-friendly version of IE10 – this update is for you.

Previously, Microsoft had disabled automatic playing of Flash content in IE10 Metro due primarily to concerns of touchscreen incompatibility, but also worries over poor performance and unruly power consumption.

However, Microsoft says it has been trawling the web, testing "thousands of domains" for incompatibilities with the Metro Start Screen variant of IE10. Microsoft claims only four percent of Flash-enabled websites fail to meet its experience goals, prompting Redmond engineers to finally release Metro IE10 users into the unprotected wilds of the web. The majority of those misbehaving websites, according to Microsoft, were due to the additional use of ActiveX controls.

In order to minimize Flash compatibility-induced user headaches, IE10 will now utilize Microsoft's IE Compatibility View (CV) system – a curated list of websites with special compatibility requirements – to disable Flash for any site deemed incompatible with immersive IE10.  This new approach is the inverse of what IE10 had been doing prior to the update, which was disabling Flash on all websites except those explicitly whitelisted as compatible.