System blue problem

[Tobi]

You need to Save to Flash and Reboot to take effect some of the new settings! 
If I click on save button and reboot,  the system has the same message. 

That's strange. Is this still the case? Can you reproduce it?

Another problem is that the System blue often emits a long beep and the LAN LED disappears. 

Unfortunately this is currently a common issue. Try to enable "Hide Hardfaults" under System menu.