Different Data Scans

Avast Free Antivirus / Premium Security
1

Why is that when I have Avast do a full system can it will can different amounts of data each time without me downloading or deleting anything?
I have gotten it to the point where it will no long have the “Some files could not be scanned”

The following is an example of what I meant…

Scan Details:
Run time: 0:57:00
Tested Files: 128860
Tested Folders: 12890
Amount of data tested: 109.7 GB
Infect files: 0

Scan Details:
Run time: 0:56:47
Tested files: 128071
Tested folders: 12816
Amount of data tested: 107.6 GB
Infected files: 0

I under there are less files and folders being tested, but I want to know why this is even if I am not myself adding or deleting any new information?

Any clarity would be most appreciated.

2

You are forgetting the fact that the os as well as many applications are using temporary files.
They may be there when scanning and not if you scan again and vica versa.

It is always a good thing to cleanup the system before scanning.
CCleaner can be used for that (Freeware)

3

Are you using the “persistent cache”?
If you are this will affect the number of files/folders scanned.
IOW once a file is stored in the persistent cache it won’t be scanned again until it is accessed/moved.
By using the persistent cache usually the scans become faster with less data needing to be scanned. 8)