Go to Desktop IE10 and click ALT --> Tools --> Compatibility View settings. Now UNCHECK the last checkmark with: "Download updated compatibility list from Microsoft".
Originally Posted by dkp23
Now you can alter the whitelist located here:
Open this file and look for these tags:
[... the domains are listed here...]
Inside these tags all whitelisted (flash-enabled) websites are listed for IE10 Metro. All you do is add your desired website inside these tags as follows:
Add as many websites as you'd like.
Now we are almost done, one last task is to delete browsing histroy. Open IE10 Metro and click WIN+I (to open settings) --> Internet Options > Delete browsing history
Flash is now enabled in IE10 Metro for the websites you have just added.