Comment 4 for bug 524169

Retested again as previous testing was broken up due to a lot of external interrupts. During installation, when the installer is discovering existing partitions, the installer pops up a prompt indicating that the drive sda has mounted partitions, and asks if it is ok to unmount them. Clicking unmount cases the partitoner to crash reporting error 141 to the installer. It is at this point that the installer enters an endless loop.