This Tutorial show you, what you can do when you got this Error: "Decompress Failed".
- Restart the Game as Administrator
- Restart the Computer (This solution has always helped me)
- Completely uninstall the game and delete any remaining WarZ files. Download the Warz Setup Exe from http://www.playwarz.com/download and create a new folder in Program Files [or Program Files (x86) when using 64-bit operating system].
Install the Game in this new folder and try to play.
- Change the Options of the The War Z launcher so that the Game always starts as Administrator
- Change the compatibility mode of the launcher for Windows XP
If nothing helps, contact the Support on https://warz.zendesk.com/home.