---
title: "What makes the scan trustworthy · DuplicateDuster"
description: "Multi-threaded hashing, folder-level and cross-drive matching, filters, read-only scanning, and an original that has no checkbox."
url: "https://royalsoftworks.com/products/duplicate-duster/features/scanning/"
source: "https://royalsoftworks.com"
format: "markdown"
note: "Markdown rendering of the HTML page at `url`. Same content, same canonical URL."
---

Features · 3 of 4

# What makes the scan trustworthy.

Multi-threaded hashing, folder-level and cross-drive matching, filters, read-only scanning, and an original that has no checkbox.

## Multi-threaded hashing

A worker pool sized at three quarters of your cores, capped at sixteen, fed in batches as threads free up — so one thread drawing a 4 GB video never leaves the others idle.

## Folder-level matching

Identical folder trees are reported as a single finding rather than hundreds of file rows, and only the topmost match in a nested run is listed.

## Cross-drive matching

Because matching is by content hash, the same file on two different drives is still recognised — a backup volume compares cleanly against the library it was taken from.

## Filters that narrow the work

Minimum and maximum size, an include or exclude extension list, skip dot-files, skip system folders. The panel badges itself while any filter is active, so a leftover setting can't quietly explain a thin result.

## Read-only by default

A scan never changes anything on its own. You see every match, with full paths and sizes, before deciding what happens to it.

## The original has no checkbox

Source-side files are rendered with a keep badge and no way to select them. There is no path through the results screen that removes the copy you nominated as the original.

[Previous Four ways to get the gigabytes back.](https://royalsoftworks.com/products/duplicate-duster/features/reclaim/) [Next The safeguards around it.](https://royalsoftworks.com/products/duplicate-duster/features/safeguards/)

[All of DuplicateDuster features](https://royalsoftworks.com/products/duplicate-duster/features/)

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