If that does not work, then reload the firmware.
You can download firmware for the DS1000E from Rigol.
https://www.rigolna.com/firmware/Then
1.Copy .RGL file to the root of USB flash
2.Power on DS1000E/D/U, insert USB into DS1000E/D/U, there will be a note that find a new firmware whether to update. Press update button
3. After finish update ,reboot and check the version
Note: Do not power off the instrument or move the USB flash during the updating.