There are really two problems here:
1) If I double click on a file, it opens in Illustrator, but it does not open with my default workspace settings. If I open the file from the file menu, my preferred workspace opens.
and
2) If I have one file open, I cannot double click on a second file and have that file open in Illustrator. I just get the little spinning circle and then it stops. I can still open a second file from the file/open menu option.
We are using CS6 and running windows 7.