Authentication Library issues are typically related to an issue with the user’s environment variables. To check this:
1. Right-click on My Computer and select Properties.
2. Click on the Advanced tab.
3. Click on the Environment Variables button near the bottom of the window.
4. Scroll through the variables looking for anything that references your Steam installation directory.
5. If you find a reference to Steam, select the variable where it is present and press the Delete button.
6. Click the OK button twice to exit.
7. Restart your computer.