<!doctype html>
<html class="no-js" lang="en" data-content_root="./">
<head><meta charset="utf-8">
<meta name="viewport" content="width=device-width,initial-scale=1">
<meta name="color-scheme" content="light dark"><meta name="viewport" content="width=device-width, initial-scale=1" />
<link rel="index" title="Index" href="genindex.html"><link rel="search" title="Search" href="search.html"><link rel="next" title="Advanced search" href="custom_file_search.html"><link rel="prev" title="How does the duplicate search work?" href="example_duplicatesearch.html">
<link rel="prefetch" href="_static/JAM_Logo_Help_Dark.png" as="image">
<link rel="prefetch" href="_static/JAM_Logo_Help_Dark.png" as="image">
<!-- Generated with Sphinx 8.2.3 and Furo 2025.09.25 -->
<title>How does the deduplication work? - TreeSize</title>
<link rel="stylesheet" type="text/css" href="_static/pygments.css?v=03e43079" />
<link rel="stylesheet" type="text/css" href="_static/styles/furo.css?v=580074bf" />
<link rel="stylesheet" type="text/css" href="_static/styles/furo-extensions.css?v=8dab3a3b" />
<style>
body {
--color-code-background: #eeffcc;
--color-code-foreground: black;
--color-background-primary: #FFFFFF;
--color-sidebar-background: #252E30;
--color-sidebar-search-background: #252E30;
--color-sidebar-link-text: #9DA0A5;
--color-background-border: #494e50;
--color-brand-primary: #FFFFFF;
--color-brand-content: #445559;
--color-brand-visited: #445559;
--color-sidebar-brand-text: #FFFFFF;
--color-background-hover: #445559;
--color-background-hover--transparent: #252E30;
}
@media not print {
body[data-theme="dark"] {
--color-code-background: #202020;
--color-code-foreground: #d0d0d0;
--color-background-secondary: #252E30;
--color-brand-primary: #F3F3F3;
--color-brand-content: #FFFFFF;
--color-brand-visited: #FFFFFF;
--color-background-border: #494e50;
}
@media (prefers-color-scheme: dark) {
body:not([data-theme="light"]) {
--color-code-background: #202020;
--color-code-foreground: #d0d0d0;
--color-background-secondary: #252E30;
--color-brand-primary: #F3F3F3;
--color-brand-content: #FFFFFF;
--color-brand-visited: #FFFFFF;
--color-background-border: #494e50;
}
}
}
</style></head>
<body>
<script>
document.body.dataset.theme = localStorage.getItem("theme") || "auto";
</script>
<svg xmlns="http://www.w3.org/2000/svg" style="display: none;">
<symbol id="svg-toc" viewBox="0 0 24 24">
<title>Contents</title>
<svg stroke="currentColor" fill="currentColor" stroke-width="0" viewBox="0 0 1024 1024">
<path d="M408 442h480c4.4 0 8-3.6 8-8v-56c0-4.4-3.6-8-8-8H408c-4.4 0-8 3.6-8 8v56c0 4.4 3.6 8 8 8zm-8 204c0 4.4 3.6 8 8 8h480c4.4 0 8-3.6 8-8v-56c0-4.4-3.6-8-8-8H408c-4.4 0-8 3.6-8 8v56zm504-486H120c-4.4 0-8 3.6-8 8v56c0 4.4 3.6 8 8 8h784c4.4 0 8-3.6 8-8v-56c0-4.4-3.6-8-8-8zm0 632H120c-4.4 0-8 3.6-8 8v56c0 4.4 3.6 8 8 8h784c4.4 0 8-3.6 8-8v-56c0-4.4-3.6-8-8-8zM115.4 518.9L271.7 642c5.8 4.6 14.4.5 14.4-6.9V388.9c0-7.4-8.5-11.5-14.4-6.9L115.4 505.1a8.74 8.74 0 0 0 0 13.8z"/>
</svg>
</symbol>
<symbol id="svg-menu" viewBox="0 0 24 24">
<title>Menu</title>
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="none" stroke="currentColor"
stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="feather-menu">
<line x1="3" y1="12" x2="21" y2="12"></line>
<line x1="3" y1="6" x2="21" y2="6"></line>
<line x1="3" y1="18" x2="21" y2="18"></line>
</svg>
</symbol>
<symbol id="svg-arrow-right" viewBox="0 0 24 24">
<title>Expand</title>
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="none" stroke="currentColor"
stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="feather-chevron-right">
<polyline points="9 18 15 12 9 6"></polyline>
</svg>
</symbol>
<symbol id="svg-sun" viewBox="0 0 24 24">
<title>Light mode</title>
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="none" stroke="currentColor"
stroke-width="1" stroke-linecap="round" stroke-linejoin="round" class="feather-sun">
<circle cx="12" cy="12" r="5"></circle>
<line x1="12" y1="1" x2="12" y2="3"></line>
<line x1="12" y1="21" x2="12" y2="23"></line>
<line x1="4.22" y1="4.22" x2="5.64" y2="5.64"></line>
<line x1="18.36" y1="18.36" x2="19.78" y2="19.78"></line>
<line x1="1" y1="12" x2="3" y2="12"></line>
<line x1="21" y1="12" x2="23" y2="12"></line>
<line x1="4.22" y1="19.78" x2="5.64" y2="18.36"></line>
<line x1="18.36" y1="5.64" x2="19.78" y2="4.22"></line>
</svg>
</symbol>
<symbol id="svg-moon" viewBox="0 0 24 24">
<title>Dark mode</title>
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="none" stroke="currentColor"
stroke-width="1" stroke-linecap="round" stroke-linejoin="round" class="icon-tabler-moon">
<path stroke="none" d="M0 0h24v24H0z" fill="none" />
<path d="M12 3c.132 0 .263 0 .393 0a7.5 7.5 0 0 0 7.92 12.446a9 9 0 1 1 -8.313 -12.454z" />
</svg>
</symbol>
<symbol id="svg-sun-with-moon" viewBox="0 0 24 24">
<title>Auto light/dark, in light mode</title>
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="none" stroke="currentColor"
stroke-width="1" stroke-linecap="round" stroke-linejoin="round"
class="icon-custom-derived-from-feather-sun-and-tabler-moon">
<path style="opacity: 50%" d="M 5.411 14.504 C 5.471 14.504 5.532 14.504 5.591 14.504 C 3.639 16.319 4.383 19.569 6.931 20.352 C 7.693 20.586 8.512 20.551 9.25 20.252 C 8.023 23.207 4.056 23.725 2.11 21.184 C 0.166 18.642 1.702 14.949 4.874 14.536 C 5.051 14.512 5.231 14.5 5.411 14.5 L 5.411 14.504 Z"/>
<line x1="14.5" y1="3.25" x2="14.5" y2="1.25"/>
<line x1="14.5" y1="15.85" x2="14.5" y2="17.85"/>
<line x1="10.044" y1="5.094" x2="8.63" y2="3.68"/>
<line x1="19" y1="14.05" x2="20.414" y2="15.464"/>
<line x1="8.2" y1="9.55" x2="6.2" y2="9.55"/>
<line x1="20.8" y1="9.55" x2="22.8" y2="9.55"/>
<line x1="10.044" y1="14.006" x2="8.63" y2="15.42"/>
<line x1="19" y1="5.05" x2="20.414" y2="3.636"/>
<circle cx="14.5" cy="9.55" r="3.6"/>
</svg>
</symbol>
<symbol id="svg-moon-with-sun" viewBox="0 0 24 24">
<title>Auto light/dark, in dark mode</title>
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="none" stroke="currentColor"
stroke-width="1" stroke-linecap="round" stroke-linejoin="round"
class="icon-custom-derived-from-feather-sun-and-tabler-moon">
<path d="M 8.282 7.007 C 8.385 7.007 8.494 7.007 8.595 7.007 C 5.18 10.184 6.481 15.869 10.942 17.24 C 12.275 17.648 13.706 17.589 15 17.066 C 12.851 22.236 5.91 23.143 2.505 18.696 C -0.897 14.249 1.791 7.786 7.342 7.063 C 7.652 7.021 7.965 7 8.282 7 L 8.282 7.007 Z"/>
<line style="opacity: 50%" x1="18" y1="3.705" x2="18" y2="2.5"/>
<line style="opacity: 50%" x1="18" y1="11.295" x2="18" y2="12.5"/>
<line style="opacity: 50%" x1="15.316" y1="4.816" x2="14.464" y2="3.964"/>
<line style="opacity: 50%" x1="20.711" y1="10.212" x2="21.563" y2="11.063"/>
<line style="opacity: 50%" x1="14.205" y1="7.5" x2="13.001" y2="7.5"/>
<line style="opacity: 50%" x1="21.795" y1="7.5" x2="23" y2="7.5"/>
<line style="opacity: 50%" x1="15.316" y1="10.184" x2="14.464" y2="11.036"/>
<line style="opacity: 50%" x1="20.711" y1="4.789" x2="21.563" y2="3.937"/>
<circle style="opacity: 50%" cx="18" cy="7.5" r="2.169"/>
</svg>
</symbol>
<symbol id="svg-pencil" viewBox="0 0 24 24">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="none" stroke="currentColor"
stroke-width="1" stroke-linecap="round" stroke-linejoin="round" class="icon-tabler-pencil-code">
<path d="M4 20h4l10.5 -10.5a2.828 2.828 0 1 0 -4 -4l-10.5 10.5v4" />
<path d="M13.5 6.5l4 4" />
<path d="M20 21l2 -2l-2 -2" />
<path d="M17 17l-2 2l2 2" />
</svg>
</symbol>
<symbol id="svg-eye" viewBox="0 0 24 24">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="none" stroke="currentColor"
stroke-width="1" stroke-linecap="round" stroke-linejoin="round" class="icon-tabler-eye-code">
<path stroke="none" d="M0 0h24v24H0z" fill="none" />
<path d="M10 12a2 2 0 1 0 4 0a2 2 0 0 0 -4 0" />
<path
d="M11.11 17.958c-3.209 -.307 -5.91 -2.293 -8.11 -5.958c2.4 -4 5.4 -6 9 -6c3.6 0 6.6 2 9 6c-.21 .352 -.427 .688 -.647 1.008" />
<path d="M20 21l2 -2l-2 -2" />
<path d="M17 17l-2 2l2 2" />
</svg>
</symbol>
</svg>
<input type="checkbox" class="sidebar-toggle" name="__navigation" id="__navigation" aria-label="Toggle site navigation sidebar">
<input type="checkbox" class="sidebar-toggle" name="__toc" id="__toc" aria-label="Toggle table of contents sidebar">
<label class="overlay sidebar-overlay" for="__navigation"></label>
<label class="overlay toc-overlay" for="__toc"></label>
<a class="skip-to-content muted-link" href="#furo-main-content">Skip to content</a>
<div class="page">
<header class="mobile-header">
<div class="header-left">
<label class="nav-overlay-icon" for="__navigation">
<span class="icon"><svg><use href="#svg-menu"></use></svg></span>
</label>
</div>
<div class="header-center">
<a href="index.html"><div class="brand">TreeSize</div></a>
</div>
<div class="header-right">
<div class="theme-toggle-container theme-toggle-header">
<button class="theme-toggle" aria-label="Toggle Light / Dark / Auto color theme">
<svg class="theme-icon-when-auto-light"><use href="#svg-sun-with-moon"></use></svg>
<svg class="theme-icon-when-auto-dark"><use href="#svg-moon-with-sun"></use></svg>
<svg class="theme-icon-when-dark"><use href="#svg-moon"></use></svg>
<svg class="theme-icon-when-light"><use href="#svg-sun"></use></svg>
</button>
</div>
<label class="toc-overlay-icon toc-header-icon" for="__toc">
<span class="icon"><svg><use href="#svg-toc"></use></svg></span>
</label>
</div>
</header>
<aside class="sidebar-drawer">
<div class="sidebar-container">
<div class="sidebar-sticky"><div class="sidebar-brand" href="index.html">
<a href="https://www.jam-software.com">
<div class="sidebar-logo-container">
<img class="sidebar-logo only-light" src="_static/JAM_Logo_Help_Dark.png" alt="Light Logo"/>
<img class="sidebar-logo only-dark" src="_static/JAM_Logo_Help_Dark.png" alt="Dark Logo"/>
</div>
</a>
<a href="index.html" style="text-decoration:none">
<span class="sidebar-brand-text">TreeSize</span>
</a>
</div><form class="sidebar-search-container" method="get" action="search.html" role="search">
<input class="sidebar-search" placeholder="Search" name="q" aria-label="Search">
<input type="hidden" name="check_keywords" value="yes">
<input type="hidden" name="area" value="default">
</form>
<div id="searchbox"></div><div class="sidebar-scroll"><div class="sidebar-tree">
<ul class="current">
<li class="toctree-l1"><a class="reference internal" href="overview.html">Overview</a></li>
<li class="toctree-l1"><a class="reference internal" href="installation.html">Installation</a></li>
<li class="toctree-l1"><a class="reference internal" href="quickstart.html">Quickstart</a></li>
<li class="toctree-l1 has-children"><a class="reference internal" href="using_treesize.html">Using TreeSize</a><input aria-label="Toggle navigation of Using TreeSize" class="toctree-checkbox" id="toctree-checkbox-1" name="toctree-checkbox-1" role="switch" type="checkbox"/><label for="toctree-checkbox-1"><span class="icon"><svg><use href="#svg-arrow-right"></use></svg></span></label><ul>
<li class="toctree-l2 has-children"><a class="reference internal" href="ribbonbar.html">Ribbon Bar</a><input aria-label="Toggle navigation of Ribbon Bar" class="toctree-checkbox" id="toctree-checkbox-2" name="toctree-checkbox-2" role="switch" type="checkbox"/><label for="toctree-checkbox-2"><span class="icon"><svg><use href="#svg-arrow-right"></use></svg></span></label><ul>
<li class="toctree-l3"><a class="reference internal" href="file_menu.html">Application Menu</a></li>
<li class="toctree-l3"><a class="reference internal" href="quicktoolbar.html">Quick Access Toolbar</a></li>
<li class="toctree-l3"><a class="reference internal" href="hometab.html">Home tab</a></li>
<li class="toctree-l3"><a class="reference internal" href="scan_tab.html">Scan tab</a></li>
<li class="toctree-l3"><a class="reference internal" href="tools_menu.html">Tools menu</a></li>
<li class="toctree-l3"><a class="reference internal" href="view_menu.html">View menu</a></li>
<li class="toctree-l3"><a class="reference internal" href="help_tab.html">Help tab</a></li>
</ul>
</li>
<li class="toctree-l2"><a class="reference internal" href="scan_targets.html">Scan Targets</a></li>
<li class="toctree-l2"><a class="reference internal" href="scantarget.html">Selecting a scan target</a></li>
<li class="toctree-l2"><a class="reference internal" href="directorytree.html">Directory Tree</a></li>
<li class="toctree-l2 has-children"><a class="reference internal" href="treesize_views.html">TreeSize Views</a><input aria-label="Toggle navigation of TreeSize Views" class="toctree-checkbox" id="toctree-checkbox-3" name="toctree-checkbox-3" role="switch" type="checkbox"/><label for="toctree-checkbox-3"><span class="icon"><svg><use href="#svg-arrow-right"></use></svg></span></label><ul>
<li class="toctree-l3"><a class="reference internal" href="charts.html">Charts</a></li>
<li class="toctree-l3"><a class="reference internal" href="details.html">Details</a></li>
<li class="toctree-l3"><a class="reference internal" href="extensions.html">Extensions</a></li>
<li class="toctree-l3"><a class="reference internal" href="users.html">Users</a></li>
<li class="toctree-l3"><a class="reference internal" href="fileages.html">Age of files</a></li>
<li class="toctree-l3"><a class="reference internal" href="top-files.html">Top Files</a></li>
<li class="toctree-l3"><a class="reference internal" href="history.html">History</a></li>
</ul>
</li>
<li class="toctree-l2"><a class="reference internal" href="drivepanel.html">Drive list</a></li>
<li class="toctree-l2"><a class="reference internal" href="snapshots.html">Snapshots</a></li>
<li class="toctree-l2"><a class="reference internal" href="disk_usage_comparison.html">Disk Usage Comparison</a></li>
<li class="toctree-l2 has-children"><a class="reference internal" href="sharepoint.html">Scanning SharePoint</a><input aria-label="Toggle navigation of Scanning SharePoint" class="toctree-checkbox" id="toctree-checkbox-4" name="toctree-checkbox-4" role="switch" type="checkbox"/><label for="toctree-checkbox-4"><span class="icon"><svg><use href="#svg-arrow-right"></use></svg></span></label><ul>
<li class="toctree-l3 has-children"><a class="reference internal" href="azure-ad-configuration.html">Azure AD Configuration</a><input aria-label="Toggle navigation of Azure AD Configuration" class="toctree-checkbox" id="toctree-checkbox-5" name="toctree-checkbox-5" role="switch" type="checkbox"/><label for="toctree-checkbox-5"><span class="icon"><svg><use href="#svg-arrow-right"></use></svg></span></label><ul>
<li class="toctree-l4"><a class="reference internal" href="certificatebased-auth.html">Certificate based authentication</a></li>
<li class="toctree-l4"><a class="reference internal" href="userbased-auth.html">User based authentication</a></li>
</ul>
</li>
</ul>
</li>
<li class="toctree-l2 has-children"><a class="reference internal" href="options_dialog.html">Options</a><input aria-label="Toggle navigation of Options" class="toctree-checkbox" id="toctree-checkbox-6" name="toctree-checkbox-6" role="switch" type="checkbox"/><label for="toctree-checkbox-6"><span class="icon"><svg><use href="#svg-arrow-right"></use></svg></span></label><ul>
<li class="toctree-l3"><a class="reference internal" href="optionsdialog-viewtab.html">Display</a></li>
<li class="toctree-l3"><a class="reference internal" href="optionsviewdirectorytree.html">Directory Tree</a></li>
<li class="toctree-l3"><a class="reference internal" href="optionsdialog-file_groups.html">File groups</a></li>
<li class="toctree-l3"><a class="reference internal" href="optionsdialog-fileages.html">Age of files</a></li>
<li class="toctree-l3"><a class="reference internal" href="optionsdialog-charts.html">Charts</a></li>
<li class="toctree-l3"><a class="reference internal" href="options-topfiles.html">Top files</a></li>
<li class="toctree-l3"><a class="reference internal" href="scan_options.html">General scan options</a></li>
<li class="toctree-l3"><a class="reference internal" href="optionsdialog-includeexclu.html">Scan filters</a></li>
<li class="toctree-l3"><a class="reference internal" href="optionsexportprinter.html">Printer</a></li>
<li class="toctree-l3"><a class="reference internal" href="optionsexportpdf.html">PDF</a></li>
<li class="toctree-l3"><a class="reference internal" href="optionsexportexcel.html">Excel</a></li>
<li class="toctree-l3"><a class="reference internal" href="optionsexporthtml.html">HTML</a></li>
<li class="toctree-l3"><a class="reference internal" href="optionsexportcsv.html">CSV</a></li>
<li class="toctree-l3"><a class="reference internal" href="optionsexportxml.html">XML</a></li>
<li class="toctree-l3"><a class="reference internal" href="optionsexportsqlite.html">SQLite</a></li>
<li class="toctree-l3"><a class="reference internal" href="optionsexporttext.html">Text</a></li>
<li class="toctree-l3"><a class="reference internal" href="optionsexportemail.html">Email</a></li>
<li class="toctree-l3"><a class="reference internal" href="optionsdialog-startup.html">Application start</a></li>
<li class="toctree-l3"><a class="reference internal" href="optionssystemcontextmenu.html">Context menu</a></li>
</ul>
</li>
</ul>
</li>
<li class="toctree-l1 current has-children"><a class="reference internal" href="file-search.html">Using File Search</a><input aria-label="Toggle navigation of Using File Search" checked="" class="toctree-checkbox" id="toctree-checkbox-7" name="toctree-checkbox-7" role="switch" type="checkbox"/><label for="toctree-checkbox-7"><span class="icon"><svg><use href="#svg-arrow-right"></use></svg></span></label><ul class="current">
<li class="toctree-l2"><a class="reference internal" href="file_search_main_menu.html">File Search Ribbon Bar</a></li>
<li class="toctree-l2"><a class="reference internal" href="file_search_searchpaths.html">Search paths</a></li>
<li class="toctree-l2 has-children"><a class="reference internal" href="basicsearch.html">Basic search</a><input aria-label="Toggle navigation of Basic search" class="toctree-checkbox" id="toctree-checkbox-8" name="toctree-checkbox-8" role="switch" type="checkbox"/><label for="toctree-checkbox-8"><span class="icon"><svg><use href="#svg-arrow-right"></use></svg></span></label><ul>
<li class="toctree-l3"><a class="reference internal" href="searchsyntax.html">Search syntax</a></li>
</ul>
</li>
<li class="toctree-l2 current has-children"><a class="reference internal" href="duplicate_file_search.html">Duplicate file search</a><input aria-label="Toggle navigation of Duplicate file search" checked="" class="toctree-checkbox" id="toctree-checkbox-9" name="toctree-checkbox-9" role="switch" type="checkbox"/><label for="toctree-checkbox-9"><span class="icon"><svg><use href="#svg-arrow-right"></use></svg></span></label><ul class="current">
<li class="toctree-l3"><a class="reference internal" href="example_duplicatesearch.html">How does the duplicate search work?</a></li>
<li class="toctree-l3 current current-page"><a class="current reference internal" href="#">How does the deduplication work?</a></li>
</ul>
</li>
<li class="toctree-l2 has-children"><a class="reference internal" href="custom_file_search.html">Advanced search</a><input aria-label="Toggle navigation of Advanced search" class="toctree-checkbox" id="toctree-checkbox-10" name="toctree-checkbox-10" role="switch" type="checkbox"/><label for="toctree-checkbox-10"><span class="icon"><svg><use href="#svg-arrow-right"></use></svg></span></label><ul>
<li class="toctree-l3"><a class="reference internal" href="searchfilter_definition.html">How do I define search filters?</a></li>
<li class="toctree-l3"><a class="reference internal" href="availablefiltertypes.html">What types of filters are available?</a></li>
</ul>
</li>
<li class="toctree-l2"><a class="reference internal" href="filesearch_templates.html">File search templates</a></li>
<li class="toctree-l2"><a class="reference internal" href="howtoexcludefiles.html">How to exclude files</a></li>
<li class="toctree-l2"><a class="reference internal" href="process_search_results.html">Process search results</a></li>
<li class="toctree-l2 has-children"><a class="reference internal" href="move_checked_files.html">Move checked files</a><input aria-label="Toggle navigation of Move checked files" class="toctree-checkbox" id="toctree-checkbox-11" name="toctree-checkbox-11" role="switch" type="checkbox"/><label for="toctree-checkbox-11"><span class="icon"><svg><use href="#svg-arrow-right"></use></svg></span></label><ul>
<li class="toctree-l3"><a class="reference internal" href="unicode_zip_files.html">Unicode ZIP files</a></li>
</ul>
</li>
<li class="toctree-l2"><a class="reference internal" href="renamedialog.html">Mass renaming files</a></li>
<li class="toctree-l2 has-children"><a class="reference internal" href="searchoptions.html">Search options</a><input aria-label="Toggle navigation of Search options" class="toctree-checkbox" id="toctree-checkbox-12" name="toctree-checkbox-12" role="switch" type="checkbox"/><label for="toctree-checkbox-12"><span class="icon"><svg><use href="#svg-arrow-right"></use></svg></span></label><ul>
<li class="toctree-l3"><a class="reference internal" href="generaloptionsfilesearch.html">General options</a></li>
<li class="toctree-l3"><a class="reference internal" href="optionsfilesearchpersonalize.html">Personalize</a></li>
<li class="toctree-l3"><a class="reference internal" href="optionsfilesearchother.html">Other</a></li>
</ul>
</li>
</ul>
</li>
<li class="toctree-l1 has-children"><a class="reference internal" href="schedule_treesize_tasks.html">Using Scheduled Tasks</a><input aria-label="Toggle navigation of Using Scheduled Tasks" class="toctree-checkbox" id="toctree-checkbox-13" name="toctree-checkbox-13" role="switch" type="checkbox"/><label for="toctree-checkbox-13"><span class="icon"><svg><use href="#svg-arrow-right"></use></svg></span></label><ul>
<li class="toctree-l2 has-children"><a class="reference internal" href="schedule_scans.html">Scheduling scans</a><input aria-label="Toggle navigation of Scheduling scans" class="toctree-checkbox" id="toctree-checkbox-14" name="toctree-checkbox-14" role="switch" type="checkbox"/><label for="toctree-checkbox-14"><span class="icon"><svg><use href="#svg-arrow-right"></use></svg></span></label><ul>
<li class="toctree-l3"><a class="reference internal" href="scheduler_options_tab.html">Options</a></li>
<li class="toctree-l3"><a class="reference internal" href="scheduler_export_tab.html">Export</a></li>
<li class="toctree-l3"><a class="reference internal" href="scheduler_move_operation_tab.html">File operations</a></li>
<li class="toctree-l3"><a class="reference internal" href="scheduler_advanced_tab.html">Advances</a></li>
<li class="toctree-l3"><a class="reference internal" href="scheduler_commandline_tab.html">Command line</a></li>
<li class="toctree-l3"><a class="reference internal" href="scheduler_schedule_tab.html">Scheduling</a></li>
<li class="toctree-l3"><a class="reference internal" href="scheduler_all_task_tab.html">All Tasks</a></li>
</ul>
</li>
<li class="toctree-l2"><a class="reference internal" href="command_line_opt.html">Command line options</a></li>
<li class="toctree-l2"><a class="reference internal" href="example_schedule_filesearch.html">How to schedule a file search</a></li>
<li class="toctree-l2"><a class="reference internal" href="howtoschedulemove.html">How to schedule a move or delete operation</a></li>
</ul>
</li>
<li class="toctree-l1 has-children"><a class="reference internal" href="tips___annotations.html">Tips & Annotations</a><input aria-label="Toggle navigation of Tips & Annotations" class="toctree-checkbox" id="toctree-checkbox-15" name="toctree-checkbox-15" role="switch" type="checkbox"/><label for="toctree-checkbox-15"><span class="icon"><svg><use href="#svg-arrow-right"></use></svg></span></label><ul>
<li class="toctree-l2"><a class="reference internal" href="notesonntfs.html">Notes on NTFS</a></li>
<li class="toctree-l2"><a class="reference internal" href="wasted_space.html">Wasted space</a></li>
<li class="toctree-l2"><a class="reference internal" href="regular_expressions.html">Regular expressions</a></li>
<li class="toctree-l2"><a class="reference internal" href="translations.html">Translations</a></li>
</ul>
</li>
<li class="toctree-l1"><a class="reference internal" href="copyrightcontact.html">Copyright & Contact</a></li>
</ul>
</div>
</div>
</div>
</div>
</aside>
<div class="main">
<div class="content">
<div class="article-container">
<a href="#" class="back-to-top muted-link">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24">
<path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8v12z"></path>
</svg>
<span>Back to top</span>
</a>
<div class="content-icon-container">
<div class="theme-toggle-container theme-toggle-content">
<button class="theme-toggle" aria-label="Toggle Light / Dark / Auto color theme">
<svg class="theme-icon-when-auto-light"><use href="#svg-sun-with-moon"></use></svg>
<svg class="theme-icon-when-auto-dark"><use href="#svg-moon-with-sun"></use></svg>
<svg class="theme-icon-when-dark"><use href="#svg-moon"></use></svg>
<svg class="theme-icon-when-light"><use href="#svg-sun"></use></svg>
</button>
</div>
<label class="toc-overlay-icon toc-content-icon" for="__toc">
<span class="icon"><svg><use href="#svg-toc"></use></svg></span>
</label>
</div>
<article role="main" id="furo-main-content">
<section id="how-does-the-deduplication-work">
<span id="deduplication"></span><h1>How does the deduplication work?<a class="headerlink" href="#how-does-the-deduplication-work" title="Link to this heading">¶</a></h1>
<p>The process of removing redundant files and replacing them by NTFS hardlinks with TreeSize is called <strong>deduplication</strong>. This will reduce the disk space that is blocked by your duplicate files.</p>
<p>Instead of having each of the files take up individual space on your hard disk, TreeSize removes all duplicate files and keeps only one of them.</p>
<p>The files that were removed will be replaced by hardlinks, which will then point to the remaining data (See: <a class="reference internal" href="notesonntfs.html#notesonntfs"><span class="std std-ref">Notes on NTFS</span></a>).</p>
<p>The data is now shared shared by all the hardlinks for this file, as shown in the image below.</p>
<a class="reference internal image-reference" href="_images/Deduplication.png"><img alt="_images/Deduplication.png" class="align-center" src="_images/Deduplication.png" style="width: 100%;" />
</a>
<p>These hardlinks can be used like any normal file. You will not notice any difference, except that the data is now shared between the other links. In fact, they are not different to any normal file, except that they do not occupy their own space.</p>
<section id="which-of-the-duplicate-files-will-be-replaced">
<h2>Which of the duplicate files will be replaced?<a class="headerlink" href="#which-of-the-duplicate-files-will-be-replaced" title="Link to this heading">¶</a></h2>
<p>If you checkmark all files of a duplicates group, TreeSize will pick the file with the newest “Last modified” date and use it as “master” for this group. All other files will be removed and replaced by hardlinks, which point towards the master file.</p>
<p>If you want to manually select a master file, you can leave one of the files in a duplicates group unchecked. This file will then not be replaced, but used as master instead.</p>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>Unfortunately, Windows Explorer does not show the size difference for a deduplicated file, or the folder that it is located in. <a class="reference external" href="https://knowledgebase.jam-software.com/7259">Read our knowledge base</a> for more information.</p>
</div>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>You cannot use hardlinks to replace files located on different hard drives.</p>
</div>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>You cannot use hardlinks to replace files located on different hard drives.</p>
</div>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>You cannot use hardlinks to replace files located on different hard drives.</p>
</div>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>All hardlinks pointing to the same file share the same “Security Description” (access permissions). Deduplication will apply a unified set of permissions to the one physical remaining file.</p>
</div>
</section>
</section>
</article>
</div>
<footer>
<div class="related-pages">
<a class="next-page" href="custom_file_search.html">
<div class="page-info">
<div class="context">
<span>Next</span>
</div>
<div class="title">Advanced search</div>
</div>
<svg class="furo-related-icon"><use href="#svg-arrow-right"></use></svg>
</a>
<a class="prev-page" href="example_duplicatesearch.html">
<svg class="furo-related-icon"><use href="#svg-arrow-right"></use></svg>
<div class="page-info">
<div class="context">
<span>Previous</span>
</div>
<div class="title">How does the duplicate search work?</div>
</div>
</a>
</div>
<div class="bottom-of-page">
<div class="left-details">
<div class="copyright">
Copyright © 1995 - 2025 Joachim Marder e.K.
</div>
Made with <a href="https://www.sphinx-doc.org/">Sphinx</a> and <a class="muted-link" href="https://pradyunsg.me">@pradyunsg</a>'s
<a href="https://github.com/pradyunsg/furo">Furo</a>
</div>
<div class="right-details">
</div>
</div>
</footer>
</div>
<aside class="toc-drawer">
<div class="toc-sticky toc-scroll">
<div class="toc-title-container">
<span class="toc-title">
On this page
</span>
</div>
<div class="toc-tree-container">
<div class="toc-tree">
<ul>
<li><a class="reference internal" href="#">How does the deduplication work?</a><ul>
<li><a class="reference internal" href="#which-of-the-duplicate-files-will-be-replaced">Which of the duplicate files will be replaced?</a></li>
</ul>
</li>
</ul>
</div>
</div>
</div>
</aside>
</div>
</div><script src="_static/documentation_options.js?v=5929fcd5"></script>
<script src="_static/doctools.js?v=9bcbadda"></script>
<script src="_static/sphinx_highlight.js?v=dc90522c"></script>
<script src="_static/scripts/furo.js?v=46bd48cc"></script>
</body>
</html>