DDE Failed to connect to TOS / ThinkOrSwim

For DDE to work between applications on Windows Vista, Windows 7, Windows 10, you must be running tymoraPRO as "Administrator".  To make sure you are, right-click on the tymoraPRO shortcut on your desktop, right-click and select properties, then "Advanced", then make sure that "Run as administrator" is checked.  If you are still having problems, you can also try setting "Run as administrator" on the thinkorswim shortcut as well.

After making these changes, shut down all tymoraPRO components and restart, and the DDE handler should now be able to connect!

Additional Note: DDE should work between either thinkorswim 32-bit or 64-bit versions.