Block keyboard and mouse input of remote user in Teamviewer session
Solution 1:
On the computer itself you need to enable it in Extras>Options>Advanced>Advanced settings for connecting to this computer>Full access.
When you are connected to remote computer use Menu Actions - disable remote input
Solution 2:
You do this from the remote computer after you have connected. When using Windows on the remote computer, Click on the "Actions" tab (Gear) at the top of the screen and select "Disable Remote Input". When remoting in from an Ipad, Click on the "Actions" (wrench) tab at the bottom of the screen and select "Disable Remote Input". I have not used Teamviewer on a Mac or IPhone so I am not sure of the exact steps. But it still should be under the "Actions" Menu.