it seems to be a windows 10 issue with avast. I complained about this issue before and was told its a known bug. scan stays at 0% till its done. but it is running.
This is a known issue, yes.
The scan stays stuck at 0% for quite a while but is running - the scan will complete succesfully. This will be fixed rather later than sooner since it isn't a major issue. We may also see some stats returned for on demand scans so when users see stats moving, they know it's not stuck.