this or to make it permanent:
To get a dialogue asking you to log in your credentials each time instead of using your default user name in IE and Chrome you need to do the following:
1) Go to IE gear icon and select Internet options
2) Move to security and select Internet and/or Local intranet zones depending on how you access you QS site (can also be Trusted sites if QS site is in trusted, otherwise skip it)
3) Push custom level button and scroll down to the bottom of the list
4) Under User Authentication Logon list, select Prompt for user name and password
This will trick IE and Chrome (it uses IE set up) to ask for your user name and password each time you want to log in into qlik sense instead of using your defaults.