By walterbays on Mar 29, 2010
Intuit support was little help, but did tell me how to create and access a verbose installer log file. That pointed me to a .NET error: "Handle does not support synchronous operations." Searching for that message I found a lot of people were getting the error with various programs including TurboTax, and with various versions of Windows running natively, as well as on VirtualBox. I did a repair installation of .NET with the Windows installer, to no avail.
Finally I tried what seemed a long shot to me: I updated VirtualBox to the latest version 3.1.6. Problem solved! The installer ran to completion, updated the program from the net, and I proceded to begin my tax return without incident.
I don't see in the change log what might have fixed the problem, but I'm grateful to the VirtualBox team!