Dopus consumes 50% CPU with mounted truecrypt volume

Dopus consumes 50% CPU time when I mounted truecrypt volume. Dopus is very, very slow in this case. I mounted a very large volume (430GB). The disk space is 30% used. The truecrypt volume is a partition volume, not a file.
Without the mounted cruecrupt volume Dopus is fast as usually.
Any ideas whats wrong?

Fred

See the FAQ on high CPU usage.