IE10 on Windows 8 and Windows RT uses the so-called CV list to determine if a site is allowed to use Flash in the Modern UI/Metro/Tile mode (Windows 8 and Windows RT) and in desktop mode (only Windows RT). This list gets updated by Microsoft and used on a daily basis by IE. It’s not only used for Flash allowance, but also for other site display requirements (e.g. forcing the site to show in compatibility mode).
Between the automatic downloads the list is kept in local store and used from there. You can edit this list and add any new sites you wish to use Flash on. At the same time you lose the automatic updating of this list, so your local copy gets out-dated over time. This does not only apply to Flash, but to other content as well. So, you may end up with sites that do not display correctly for you anymore, either because they were not removed from or were not added to your local copy of the CV list. Please bear this in mind when you start editing the file. When you observe problems with a site, first check if the problem couldn’t be caused by absence/presence of the site on the CV list and always mention that you are not using the up-to-date CV list when you ask for help!
The basic procedure is:
- stop updating of the CV list
- edit the local copy
- flush the IE cache
In desktop mode IE press ALT, go to the Tools menu, click Compatibility View Settings, uncheck the mark “Download updated compatibility lists”. Clock “Close”. (Do not try to add sites manually in this dialog, it will not work for Flash.) Close all IE instances.
Open Notepad. Open Windows Explorer, type the following in the address bar: “%localappdata%\Microsoft\Internet Explorer\IECompatData\”, hit Enter. This opens to a folder in your profile that should contain a single file: iecompatdata.xml. Drop this file on Notepad.
Open Edit and Search for “/flash”, this sets you at the end of the “Allow Flash” section in the list. Now you can add any of your desired sites right before the closing “</Flash>” tag as <domain>example.com</domain>. Most easily done by a copy and paste of the last entry in the list. You can only enter raw domain and host names, no paths, protocols, slashes etc. When you are finished save the file and close Notepad.
As a last step you need to flush the internet cache. First flush the cache of desktop IE at Internet options, General, Browsing history. Click the Delete button and check the first four categories, click Delete. Once IE is finished go to the Modern UI, open IE on it, open the Charms Bar, click Settings, click Internet options, click Delete button beneath Delete Browsing History section. Once this is finished close the IE app and reopen it.
You should now be able to view Flash content on all sites that you added to your local CV list. I verified that this works with the modern UI IE on Windows 8. I do not know but assume it works on RT devices as well (please use comments to confirm).
Remember what I said about your local CV list growing obsolete over time! You may want to update the list from time to time. To do so rename your existing file, reenable the automatic download of the list and wait. You may need to flush your cache again and visit at least one website. I can’t tell you the exact order of steps, but after a few minutes of trying this and that the list suddenly appeared. Now you can “re-inoculate” the updated CV list with your desired sites.