X-RiteColor Master software communicates with a wide variety of X-Rite (and some 3rd-party) instruments. A common helpdesk call relates to the failure of these two entities to communicate. Try the quick checklist below. Unless there is a damaged cable or a hardware failure (instrument or PC), this will generally get you going again.
Ensure that you have selected an appropriate database
"CM1", or 0°/45° for: 900 series, 500 series, CA22 or CF57.
"CM2", or Sphere for: SP series, 8000 series* or CFS57.
"CM3", or Three-Angle for MA58.
"CM5", or Five-Angle for MA68.
Check the interface cable and power adaptor
Look for damage - if you have a spare, experiment.
Disconnect and reconnect cable - inspect connectors: look for bent contacts.
Ensure the instrument is receiving power.
In X-RiteColor Master, ensure the COM port is selected and configured
From the command line select "Options / Instrument Port" - Usually "COM1".
From the command line select "Options / Instrument Mode" - Usually "Normal".
Ensure instrument is properly configured
Baud should be set to 9,600.
Handshake should be OFF.
Disable any other software that might use or confuse the COM ports
Palm Pilots are notorious. Ensure Palm software is not running.
Some anti-virus software can block communications.
Inspect Windows "Device Manager"