DavidR
3
It may be advisable to pause the avast on-access scanner after you have safely arrived at the on-line scanner web page.
Two AV scanners running at the same time could cause a conflict (some on-line scanners download a virus pattern file that may trigger your resident AV {Panda’s does this}). What/which AV deals with a possible infection if on is found, are both trying to repair/delete/move the infected files? I think you can see the possibilities for conflict.
The main reason you go to an on-line scanner is to provide confirmation (a second opinion) that your system is clean (or not), in which case you wouldn’t want your existing AV getting into the mix.