Incomplete scans by 4.7

Avast Free Antivirus / Premium Security
1

I have discovered an anomaly with AVAST 4.7 that raises serious doubts about its reliability and thoroughness. Scanning the same file/folder by different means yields vastly different results.

I have an I: volume 36.5 GB with 6 folders; one folder, Security Files is 36.1 GB; it has 9 files, each over 4 GB.

When I go to Windows Explorer, right click the Security Files folder, then select the Avast Scan Security Folder option, AVAST Quick Scanner seems to very diligently scan through the 36 GB. It takes about 40 Min’s. This is only for reference. No problem here; I am glad it is doing a thorough scan. I would expect it to do as well in all other cases.

However, when I click on the AVAST Icon and then choose the Folder Selection option; then go to the Security Files folder or the entire I: volume, I get vastly different results from the above scan. I takes Avast only 6 Seconds to scan the whole volume; it takes it 00:00 seconds to scan the 36.1 GB Security Files (vs 40 minutes to scan it from Windows Explorer). Obviously Avast is skipping over the large files in the Security Folder. (The Scan Archives option is selected. No error or exception message.)

I haven’t tested it, but I see no reason the scan Local Drives or the full system scan would do any better.

If Avast is going to just skip over files, under different circumstances, how can it be trusted?

If it does skip over files, how do we know it?

This anomaly raises serious questions about Avast’s reliability and thoroughness.

I am anxious to hear the explanation for this.

boblav

2

I believe the obvious question is: what sensitivity did you select for the “Folder selection” scan?
The Explorer Extension scanner uses the highest possible sensitivity, corresponding to the “Thorough” scan from the Simple UI.

3

Thanks, Igor. You’re right, I had selected Standard Scan rather than thorough. I had erroneously interpreted the scan sensitivity as applying to the Scan Archive option at the bottom of the box.

Interesting point----The Quick scan invoked from Windows Explorer is far different than the Quick Scan invoked from Avast control panel.

Thanks again for your quick response.

boblav

4

Well, you are right that the words “quick” are not related here.
The “Quick Scanner” (Explorer Extension) is called that way because it’s meant for a quick check of a file or folder (i.e. without having to start the ordinary scanner, select areas, review the results…); the name doesn’t really have anything to do with the scan sensitivity.