Symptoms might include:
To calibrate and profile a monitor successfully, access to the video Look Up Tables (LUTs) on a computer’s graphics/video card is required. The LUTs is where the calibration curves for the monitor reside. Profiling software (like i1Profiler and ColorMunki) needs to reset the LUTs before running a new calibration and will later store the newly created calibration curves to these LUTs.
If access to the graphics card is not working, the calibration might fail. It might also deliver unexpected calibration results or the "Before & After" preview at the end of the calibration. Another common symptom is that the calibration will not be re-loaded, when restarting the computer.
Windows systems tend to have more conflicts with access to the graphics card. On Mac, this is rarely seen. To solve such issues and ensure proper calibration quality please consider the following hints: