I may miss a step, because I had only glimpse at the replys.
However, if you are switching from 2009 to 2010, I have some recommedations.
1 - Make a copy of your 2009 file with something like 2010 or 10 on the end. You can do that from the 2009, or just with the Windows Copy command.
2 - Open the ....2010 file with your ST2010. I expect, it will behave as mine did when I went from 2007 to 2009: It should ask if you want the file converted. To which you would say yes. All of your pushpins should make the jump to the new program. (See below for why I say "should".)
3 - When you resave the file, it will have the 2010 settings embedded. Therefore, you will NOT be able to open it with the 2009 program.
My reason for suggesting the second file, at least for the time being, can be traced to some issues I encountered when I changed to the 2009. In the 2009, Microsoft removed a lot of their pushpins. I had been using my ST while delivering pizzas. And I was using the number pushpins as part of the address for locations to help me find houses better. With them removed in the 2009 version, they were replaced by generic pushpins. So, I remade them and brought them back into my file.
Anyhow, good luck in the update. I've just started reading the forum again. I no longer do deliveries, so my laptop stays home, now.