I went through a lot of the trouble that people describe here, and did several jumps back and forth between version 3 and 4. No systematic work here, I just kept running like a rat in a labyrinth Upgrade always stopped with option to enter safe mode, which did not work, only giving me a black screen with a single dead underscore. Enter Transporter. I read a post about it here, thank you to the one posting it! With Transporter, I could use the hd image backup to get a new VM based on my old hd image. I kept using the "magic" keys to get manual access during upgrade, to supervise and deflect the various "new device" prompts. After a lot of restarts, initiated by the upgrader, I am now the happy owner of a working parallels 4. And it does seem to be a nice app. To bad about the somewhat faulty installer. I hope the team will get it up and running soon.
A few questions: How do you get a HD image backup - or where is it located? How do I use Transporter? Where was that post on transporter located thanks in advance - or
The backup is were you saved it when prompted before conversion to v4 format. By HD image I mean the .hdd file that Parallels Desktop use as hard drive for the Virtual Machine. This is the post I refered to, by nice user sharkmeat. It proved helpful to me: http://forum.parallels.com/showthread.php?t=31326