142                                    Keysight X-Series Signal Generators Error Messages
Error Messages
List of Error Messages
            in secure mode can only be increased.
644 Firmware extension module error; Cannot load extension module due to
     missing file ({name}).
            This error indicates that specified file containing code for self
            test or calibrations is missing. Report this error to service
            office.
644 Firmware extension module error; Failed access to operation in
     calibration extension module({value}).
            This error indicates that there was a problem accessing a specified 
            operation in the calibration extension module. This can occur if
            the calibration extension module is corrupt or missing or does not
            contain the referenced operation.
644 Firmware extension module error; Specified operation number ({value})
     does not exist.
            There was a problem accessing a specific operation in one of the
            extension modules. This occurs if the extension module is corrupt
            or missing or does not contain the referenced operation.
645 License specification error; {name}
            The file may be corrupt or the firmware may need to be upgraded to
            understand the license specification.
646 Default path not found on USB; To use the external media as the user
     file system, you must choose an  existing path on the external media.
     Current path is '{name}'.