This will have to change for me to continue using Avast as my AV client.
ClamWin has this functionality (on-demand) without the service, so I could use Avast + ClamWin (and disable the per-user AvastUI process), but I might as well find a program that has both the service as well as an on-demand scanner.
(This is not an attack against you, Tech, but a comment for the developers.)
The scanning doesn’t run in AvastUi.exe, but rather in the AvastSvc service.
What the AvastUi does provide, however, is all the GUI - including the one you see after you use the rightclick Scan option. So this is unlikely to change.
I don’t think Avast has to make a separate GUI, but it would be nice if they lightened the GUI allowed it to run on-demand without planting it as an ever-present process for my session. As it stands, the GUI all of a sudden acquired bloat and inconvenience (which Avast4 may have had, but it didn’t force me to interact with the GUI much).