"Unable to capture remote screen, fast user switching..." windows 10

Hi,

I have some troumble giving remote assistence to our domain users.

If we must do something that require admin right in windows, a window opens with the message "Unable to capture remote screen, fast user switching..." (due to UAC) and it's impossible to insert admin credential to proceed. Often, remote keyboard is disable.

• Remote client use Teamviewer QS, have Windows 7/10 and it isn't admin of the client
• helpdesk uses Teamviewer 11 on windows 10 and have admin rights

can you help me?
many thanks