DAEMON Tools Ultra supports Windows 10 Anniversary starting from 4.0 version. If the older version was installed before the update, after it, the unistallation may not work.
To update to the next release, please follow the steps:
Close DAEMON Tools Ultra and tray agent.
Go to the installation folder (C:\Program Files\DAEMON Tools Ultra is a default path) and remove it completely.
Download the newest version from the official site.
Install the newest version following these steps.