I ran into problems with my wife's cube. I used carbon copy cloner to take a full backup first and I'm glad I did. After the upgrade in place I got multiple application core dumps (exception error). This would happen in Entourage, Safari and Word. I moved back the partition and then used the archive & reinstall. That worked fine for me, YMMV. Ann wrote: I am planning a "dirty" install, just overlay it over Jaguar. My girlfriend did both her 12" Powerbook and her Sonnet accelerated Cube last weekend and she hasn't reported any problems. Anything I should be aware of before installing it on the cube?