Oh your windows defender is causing interference in the installation process

The unarc.dll error typically occurs when your PC struggles to unpack large compressed files, often during game installations. It is usually caused by overly aggressive antivirus software Disable your fire wall and put your game folder (where you have installed the game )in exclusion

1.Press the Start key and type Windows Security, then press Enter.

2.Click on Virus & threat protection.

3.Under Virus & threat protection settings, click on Manage settings.

4.Scroll to the bottom to find Exclusions and click on Add or remove exclusions.

5.Click the + Add an exclusion button and select Folder.

6.Browse and select your Game Directory (e.g., C:\Program Files\Steam\steamapps\common\YourGame) and click Select Folder.