1) Uninstall Wolfteam via the Control Panel
2) Delete the AeriaGames folder from C:/ drive. The AeriaGames folder will be in the following path location "C:\AeriaGames
3) Delete your old Wolfteam Installer.
4) Disable your Firewall
and Windows Defender
5) Clean the Registry by installing and running CCleaner
which is a Registry Cleaner.
6) Re-download the Wolfteam Installer from Aeria
7) Re-install Wolfteam and let it download all the patches, don't interrupt this process.
8 ) Make sure you run the game Launcher as an Administrator - Right click on the launcher icon, and select the option "Run as Administrator