Having used AVG I found that it slowed everything down while it was scanning.
This week I have replaced it with Avast.
It is programmed to start a scan at 12 noon each day. Now, after 30 minutes it has scanned 5%. Seems like it's going to take some while to scan my system. Is this an unusually long time - 30 mins for 5%?
some systems offer a quick scan and a deep scan; if you have the choice, go for the former (and set it to do it while you're having dinner). You should only need the occasional deep scan.
Avast has both quick and full scans; on my machine (1TB HD) a full scan takes about 1.5 hrs but I haven't done one with the very latest version which now displays a percentage rather than the progress bar that previous versions used. I doubt that they would have made the core function of the software significantly slower than before, but I never kept track of how quickly the progress bar used to fill to see if it got quicker towards the end of a scan.
I could be wrong, but it is my opinion that, having done a full scan of everything which is in one's computer, it is then only necessary to regularly undertake 'Quick Scans' which will (or should) scan anything further which has entered the computer........Seems to work for me.
Incidentally I am all in favour of MSE. However,it looks as if ummmm is still scanning with hers.!!
incidentally, quick scans being really pretty quick - maybe five minutes - means you don't have to set them up to be done regularly, just start one when you're taking a screen break. You should be able to do it from the desktop icon.