: To prevent it from happening again, go to your antivirus settings and add the game’s installation folder as an Exclusion or Allowed folder . Advanced Solutions

Temporarily disable your antivirus software to see if it's interfering with Steam:

Try running the game in compatibility mode:

Completely close Steam (check your Task Manager to ensure it's not running in the background). Right-click the on your desktop. Select Run as administrator . Try launching the game again. 3. Clear the Steam Download Cache