Revert to factory settings and delete all presets/settings
In KLANG:app login to the device you want to revert to factory reset. Go to CONFIG > INFO > SET > Factory Reset. Enter the last digits of the serial number and wait until the unit has fully booted.
On :kontroller alternatively go to the CONFIG menu > NET > Expert > Reset Factory defaults.
If unable to login there is another way for :kontroller, :vokal, :konductor, DMI-KLANG: place an empty file deletePreset (no file extension, download ZIP here) besides the KOS Update files and run the update procedure: KOS Update | 2nd Gen. Processors
For :vier and :fabrik follow this step-by-step guide.