As of January 2014, there has been a new version of Java that prohibits the Java applet for scanning with the Lexmark X543 network scanner.
Here below, you can see a quick description of how to fix the issue on Windows 8.
First, open the Control Panel and select Java.
in the Control Panel, go to the Security tab and click the edit site list button.
In the menu, add the HTTP address of your Lexmark printer. In the example below I have used the address of my printer 192.168.1.7, you need to choose the address of yours from your web browser.
Once this has been done, restart your browser and navigate to the printer page, and check that it is working. When you activate the Java on the page, make sure that you change the setting as follows.
This will make it so that you don't need to accept any pop-ups when using your network scanner.
I hope that this helps you in case you run into this problem.
