Arduino Mega 2560 EEPROM corrupt. How to recover it?

Hello!
I hope this is the right place for it.

I got an original Arduino Mega 2560 in my 3D-Printer and i use Repetier Host(RH) to write/read the EEPROM values for it. Since one week RH tells me:

"Info: Configuration reset to default. Save data in EEPROM.
EEPROM corrupt. Default values have been loaded."

Now i still can change the EEPROM values (e.g. X-,Y-,Z-Offset values) in RH and it shows me the values i have entered but my printer doesn't use the new values.

Does anyone know how this can happen and what I can do about it? And can i still use the Arduino or do i need a new one?

Thanks for your help!