Hi Abrarul, welcome to the forum
Avast - Settings - Tools - Sandbox - Customise - Virtualised processes - select Chrome - Delete - Ok - Ok.
For your understanding, there are two ways to Sandbox a process :
1 ) Via the menu I posted above.
2 ) Or right click on a Shortcut ( from Chrome) and choose "Run inside sandbox" or "Always run inside sandbox".
"Run inside sandbox" does that only once, and "Always run inside sandbox" of course always untill you change that.
And when you have chosen "Always run inside sandbox", you can right click on the Shortcut again and choose
"Run outside sandbox" or "Always run outside sandbox".
Personally I have the Shortcuts from my browsers on my desktop, and handle everything from the right click menu.
Greetz, Red.