VST-Player I had the same problem at the beginning when I used Garritan CFX grand on a Mac.
The only setup that worked and completely eliminated any crackle was
Max engine RAM : 1.5 GB ( allocating more RAM generated cracks)
Pre caching : 32 kB
BSize : 64
BSize Max 64
Half Pedalling on
Reverb off ( it is a crime to add additional reverb to Garritan, as it’s natural recorded reverb is what makes the product unique, as it’s abbey road studio 1)
Also, make sure you to use a fast SSD , minimum transfer rate being 500 MB/ s
Switch off anti viruses and turn wIfi off , as this can generate system interrupts that will cause crackles because of context switching in processing .
With these settings, no crackle even with long sequence of chords with sustain and excellent playability only second to pianoteq .