I'm chiming in to say that being able to have two years (at least) of TurboTax running at the same time on my computer is a huge issue for me as well. I have used TurboTax Home and Business (or some prior version) for over 20 years, ever since I opened my small business. I *always* open the past year while I'm working on the current year, for exactly the reasons people have identified above, and because it allows me to make sure I'm being consistent in how I answer and fill in the information from year to year. If I have already figured out how to answer questions, I do not want to be slowed down by having to figure it out again. Being able to check on details from prior years, and to cut and paste answers to questions. I don't have two computers, so that won't work for me.
I've perfected a system of doing my taxes over the past several years to make it go as smoothly as possible for me, and I need this. The PDFs don't lay out everything in the program in the way I need to see it done.
I hope that Intuit will fix this problem for next year and beyond.
