When you open the Avast user interface it will tell you which version it is.
But you have a paid version, with the Sandbox, but you have never used it.
Ok, can you look here :
Avast - Settings - Tools - Sandbox - Customise - Virtualised processes
Is there anything listed under " Vitualised processes " or " Vitualised folders" ( see screenshot ) ?
When yes, click on each and every item, and delete them from those lists untill there are no more items listed. And see it that helps.
When nothing is listed there, simply tell me.
Greetz, Red.