Thomas Gratz, the Project Spark Community Manager just announced that Project Spark has been sunset and pulled from Xbox Marketplace and Windows Store.
If you already own Project Spark, the online service will be shut down on August 12 and that’s your deadline to download and upload user created content. Project Spark was already transitioned from active development in fall last year but this is the plug officially being pulled on it.
Players who bought and redeemed the Project Spark Starter Kit at retail between October 5, 2015 and May 13, 2016 will get credit in their Microsoft account.
Source: God is Geek