Unable to scan

Avast Free Antivirus / Premium Security
1

Full System Scan found 0 infections and 17 files unable to scan.
How can I identify the files that cannot be scanned?

2
How can I identify the files that cannot be scanned?
Ignore it, avast is just telling you it could not scan those files for whatever reason (there can be many) and there is nothing you can do about it. This is something that happens with all security programs but it is not all that display it in the log. It is also something avast is planning to remove

It does NOT mean they are infected

Here is some info from 2014 https://blog.avast.com/2014/02/28/how-do-i-handle-files-that-avast-cant-scan/

3

Have you looked in the Scan History ?
AvastUI > Protection > Virus Scans > Scan History.
This assumes that you have elected to Generate report file in the scan settings (or that is the default).