I have just tried the new Mac OS X VM (Squeak 3.8.20beta1U) and have noted that when saving image located on an nfs mount, all the system is blocked probably on a network lock. When saving image located on a local disk all seem ok. When using Mac OS X VM (Squeak 3.8.18beta4U) and saving image located on an nfs mount, it's ok.
My system: - Mac OS X 10.4.11 - Dual 2.3 GHz PowerPC G5
Best regards. Alain