If your spectral display is not displaying properly in Cygnet:

Please update to the latest version of Cygnet - to get the latest Java version that is included with Cygnet.

If that does not solve the problem, make sure to update your video drivers.

If the spectral display is not completely blank, but appears to be starting and stopping, check your EEG signal and artifact inhibit settings. A large signal that exceeds the artifact inhibit settings will cause the spectral display to pause until the artifact has passed. Improving the electrode connection so that it does not trigger the artifact detection, or raising the artifact inhibit slider, should resolve the issue.