Enabling Compact OS is simple and easy, as following: 1. Press Windows Logo + X, or right click on Windows Logo Run CMD with Admin privileges 2. Before running Comress command, I recommend you to check current used space (Windows folder or system partition). Run CMD>compact.exe /CompactOS:always 3. At the end I got 3.63 GB of free space on my personal PC, and ca 500 MB on my tablet. On another tablets where I tested CompactOS, before this article, I got 1GB - 2GB of free space. 4. If you want to turn off compression of OS, then you need to type command: CMD> compact.exe /compactOS:never