"Could not complete your request because Photoshop does not recognize this type of file"
If you receive this message, it is because you are trying to open the Topaz plugin directly from its file location, which will not work.
To access Topaz in Photoshop, you must do so from the Filter menu inside of PS. If Topaz is not located in the Filter menu, please see here on how to access the plugins in Photoshop & Photoshop Elements, as well as Photoshop Creative Cloud.
My Topaz plug-ins are grayed out in the Filter menu.