DantzLab has tested Retrospect extensively on the Power Macintosh and found that Retrospect 2.0B can fail when running in a stressful Virtual Memory environment. By stressful, I mean a situation in which Virtual Memory is set much higher than built-in RAM and a large block is allocated to Retrospect. Although Retrospect runs fine with Virtual Memory in a less stressful configuration on Power Macintoshes (Virtual Memory set to only a few megabytes over real RAM), the safest approach to running Retrospect 2.0 or 2.0B on a Power Macintosh is to run with Virtual Memory disabled. Remember, there are no problems with Virtual Memory and Retrospect on 68K Macintoshes.
This problem has already been fixed in our upcoming PowerPC-native release, Retrospect 2.1, which will be available in May. In all other respects Retrospect 2.0B is behaving just as well as it has on the 68K Macintosh.