I have a late 2010 iMac on which I have been running 10.6.8 because of some legacy applications I needed for work. I have also been running Windows 7 Pro via Parallels Desktop. Over the past week I have developed network issues where the iMac can not get a proper IP address to connect to our local area network servers. I have purchased an external firewire drive on which I have installed 10.9.2. When I start up with 10.9.2, the IP issues appear to be resolved. My questions about migration are: 1) Do I have to migrate all of my applications from my 10.6.8 user folder to my 10.9.2 user folder or can I run the applications from the 10.6.8 Applications folder? 2) What, if any, problems will I encounter if I do not migrate the applications? In order to keep working I'm still running 10.6.8 without access to our local servers, but I still have internet and email access. I just don't want to start using my applications under 10.9.2 until I know what to expect. Thanks for any insights.