If you overload your computer processor (too many demands by your sequencing software), this may occur. Always watch the Performance meter of your host, and use our optimizing tips to conserve CPU power:

1 Setting the polyphony
Unused voices do use a little CPU when not used, especially at higher settings. a manual setting of 40 voices for a piano part that will end up using 16 voices means wasting a lot of CPU. Try to measure how many voices your MIDI part uses, and set the polyphony display accordingly. You can also try to lower the setting and listen to missing notes.

2 enabling 32 bits mode
This switch trades a little RAM against about 10-15% of CPU usage. If you have enough RAM in your computer to load the sounds in 32 bits mode, always use this. It is not very noticeable in presets where no transposing occurs (like drums or drum loops), and very noticeable in preset where a lot of transposition occurs (like synth or bass presets)

3 filters out
Disable the multimode filter when not in use. Do this by turning off all filter type buttons. Do the same with the UVI-Filter™ by placing the cutoff at its center detent position. (Command-click on mac, alt click on PC)

4 release time
Make sure that notes don’t continue playing because of a long release time. This is especially true when parts are played with sustain pedal, and it can mean many notes are still playing in the background