More of an FYI and a call out to the group to see if anyone else is seeing the same issues. We have been updating some of our users to newer machines that are shipping direct from Apple with 10.9. The Users current OS is 10.8.5 fully up to date and under full disk encryption. The 10.9 machine has been test from a deploy studio image as well as fresh out of box. The issue is when you start Migration Assistant it never finds the 10.85 drive, or if it does,It states the migration is only 157kb worth of data to be moved . The workaround that we've found so far, albeit not the best, is to turn off file vault on the 10.8.5 machine. Once that is completed it shows up correctly and can be migrated to the 10.9 machine.
If anyone else is seeing this and has found a different way to combat this please let me know. Or if you are seeing the same thing please feel free to comment as I'm raising a ticket with Apple
I posted this in the other thread you started, but i'll repeat here in case you didn't see it. I'm experiencing the same issue. the work around for me, has been to open migration assistant on the old computer, select "transfer TO another mac" and then on the new machine, open migration assistant and select "transfer FROM old mac/drive/boot volume" after you confirm the code, the data should show up.
i found a script someone wrote that mounts the source drive as root about 10-15 seconds after you start migration assistant. The issue is migration assistant kills everything and basically logs out to start it. I have the app on my mac but need to find the source. I will post it when i find it