If you're computer is currently running an older version of the Teamstream, in order to upgrade, you will need to completely uninstall the previous version first.

Delete "C:Program Files (x86)Toyota Diagnostics" entirely, then you can install the latest version of Techstream.

Note: If any function button is disabled or missing, it may be because windows has installed too many different types of software. Installing it on a fresh copy of Windows may solve the issue.