Norton
does use trust/reputation and past scans to reduce work, but a manual
Full System Scan is still designed to be very thorough, so the total time often does
not decrease much (or at all) between runs.
How Norton handles trusted/already‑scanned files
Norton has features like
Insight / reputation / file trust that are meant to:
- Identify files that are very common and considered low‑risk
- Reduce how deeply or how often those files are scanned
- Focus more effort on new, rare, or changed files
However, there are a few important points:
- A manual Full System Scanusually behaves more like a “belt and suspenders” check. Even if a file was clean before, Norton may still rescan it after:
- New signatures/definitions are downloaded
- The scan engine has been updated
- A certain amount of time has passed
This is by design, so that new detection methods can catch threats that were previously missed.
- Norton’s trust/reputation system often helps more with:
- Real‑time protection (on‑access scans while you use the PC)
- Idle/background scans and quick scans
…than with the wall‑clock time of a full, explicit “scan every corner” job.
- Even when “trusted” files are optimized, Norton may still:
- Read file metadata or a small portion of the file for quick checks
- Walk every folder and file entry on disk
So disk I/O overhead is still there, and that alone can keep total scan time similar.
- If you have:
- A lot of small files (source code, logs, browser caches, etc.)
- A mechanical HDD instead of SSD
- Aggressive settings (scan inside archives, network drives, etc.)
…full scans will tend to take about the same time every run, regardless of caching.
What you can do in practice
If you mainly care about security, not benchmarking scan time:
- Use Quick Scan or the default Smart/automatic scans for regular use.
- Reserve Full System Scanfor:
- Occasional health checks (e.g. once a month)
- After risky behavior (unknown software, suspicious devices, etc.)
- Check your Norton settings for things like:
- Archive/compressed file scanning
- Network drive scanning
If you don’t need those, disabling them can noticeably reduce scan time.
Summary
Norton
does have mechanisms to trust and optimize already‑known files, but its
Full System Scan is intentionally conservative. Because it re‑evaluates files after signature/engine changes and still has to walk the whole filesystem, you often won’t see scan times “learn” and drop the way you might expect, even though protection is still taking advantage of trust/reputation in the background.
