That's really interesting and you may have shed light on my problem.
I set my sandbox storage to my second hard drive, away from the default 'same drive as the modified file', since then whenever it gets too full I have to create another sandbox directory, incremental, i.e. AvastSB2, reboot then delete the preceding folder, AvastSB1.
I do get the occasional message that the sandbox is deleting when the button is pressed, but always that something is using it and a reboot is required.
This is when nothing is running at all in the sandbox?
![Huh ???](https://forum.avast.com/Smileys/default/huh.gif)
?
UPDATE:
Set option back to default and it works again!
Why give the option of moving the sandbox storage location if when you do, it breaks?
![Roll Eyes ::)](https://forum.avast.com/Smileys/default/rolleyes.gif)
On version: 8.0.1483