why can't I attach to my process?

I can start debugging (F5).

If I start with Ctrl+F5 and then go to attach later I am unable.

The program name is grayed out. The attach button is disabled when I select the row for the program.

I've tried using Attach to "Automatic" or picking Managed 4.0 + Native.

I've tried checking both "Show processes from all users" and "Show processes in all sessions"

I'm running Visual Studio as an administrator.

Any ideas?