The game does not start

Sorry to hear you are having trouble.

Please try whitelisting the game with any anti-virus software installed.

Or this suggestion from the support FAQ if the above doesn't work.

Error: Could not create your Galactic Civilizations IV user data folder. 

On Windows, go to your 'Windows Defender Settings' --> 'Virus and threat protection --> Ransomware protection --> Turn off 'Controlled folder access':

https://support.microsoft.com/en-us/windows/allow-an-app-to-access-controlled-folders-b5b6627a-b008-2ca2-7931-7e51e912b034 

Thank you for your patience and patronage.