Yesterday a new build, version 9901, of Windows 10 leaked onto the web and many people were likely curious to try it out. However, installing this version will break your Insider update cycle and you won’t receive further builds.
Source: Installing leaked Windows 10 build 9901 will break your Insider update cycle - Neowin
https://twitter.com/GabeAul/status/544216234980421632
All I can say is "ha ha" to those who thought they were being smart ))