{"id":"duplicates.how-does-storage-studio-decide-two-files-are-duplicates","url":"/faq/duplicates/how-does-storage-studio-decide-two-files-are-duplicates","category":{"id":"duplicates","title":"Duplicate files"},"subcategory":{"id":"basics","title":"Duplicates basics"},"question":"How does Storage Studio decide that two files are duplicates?","alt_questions":["Does the duplicate finder compare file names or contents?","How accurate is Storage Studio's duplicate detection?","Are duplicates matched by name or by content?","How do you know two files are identical?","duplicate detection by content mac","Could it mark two different files as duplicates?","What counts as a duplicate in Storage Studio?"],"short_answer":"Only files whose full content is identical are treated as duplicates. Names, dates and folders don't matter, and similar-but-different files such as two edits of one photo aren't flagged. Cloud accounts are compared using the provider's own content fingerprints, so nothing is downloaded.","answer_markdown":"Two files count as duplicates only when their full content is identical. Names, dates and folders don't matter — a file called \"Invoice.pdf\" in Downloads and \"March invoice.pdf\" in Documents are a duplicate set if their contents match exactly, while two files with the same name but different contents are not.\n\nWe don't publish the details of how files are compared, but here's what it means for you: on your Mac the whole content of each candidate is checked, not just the start of the file or its size, so a set only appears when the copies really are the same. In cloud accounts, Storage Studio uses the content fingerprints your provider already keeps for each file, so nothing has to be downloaded.\n\nSimilar-looking files — two edits of the same photo, or a song in two formats — aren't exact copies, so they're not shown.","answer_html":"<p>Two files count as duplicates only when their full content is identical. Names, dates and folders don&#39;t matter — a file called &quot;Invoice.pdf&quot; in Downloads and &quot;March invoice.pdf&quot; in Documents are a duplicate set if their contents match exactly, while two files with the same name but different contents are not.</p>\n<p>We don&#39;t publish the details of how files are compared, but here&#39;s what it means for you: on your Mac the whole content of each candidate is checked, not just the start of the file or its size, so a set only appears when the copies really are the same. In cloud accounts, Storage Studio uses the content fingerprints your provider already keeps for each file, so nothing has to be downloaded.</p>\n<p>Similar-looking files — two edits of the same photo, or a song in two formats — aren&#39;t exact copies, so they&#39;re not shown.</p>","answer_text":"Two files count as duplicates only when their full content is identical. Names, dates and folders don't matter — a file called \"Invoice.pdf\" in Downloads and \"March invoice.pdf\" in Documents are a duplicate set if their contents match exactly, while two files with the same name but different contents are not.\n\nWe don't publish the details of how files are compared, but here's what it means for you: on your Mac the whole content of each candidate is checked, not just the start of the file or its size, so a set only appears when the copies really are the same. In cloud accounts, Storage Studio uses the content fingerprints your provider already keeps for each file, so nothing has to be downloaded.\n\nSimilar-looking files — two edits of the same photo, or a song in two formats — aren't exact copies, so they're not shown.","tags":["duplicates","how it works","exact copies"],"related":[{"id":"duplicates.does-it-find-similar-photos-or-only-exact-copies","question":"Does Storage Studio find similar photos, or only exact copies?","url":"/faq/duplicates/does-it-find-similar-photos-or-only-exact-copies"},{"id":"duplicates.do-files-with-the-same-name-count-as-duplicates","question":"Do files with the same name count as duplicates?","url":"/faq/duplicates/do-files-with-the-same-name-count-as-duplicates"},{"id":"duplicates.does-duplicate-scanning-download-my-cloud-files","question":"Does checking a cloud account for duplicates download my files?","url":"/faq/duplicates/does-duplicate-scanning-download-my-cloud-files"}],"applies_to":"all","last_reviewed":"2026-10-01","title":"How does Storage Studio decide that two files are duplicates? — Storage Studio FAQ","description":"Only files whose full content is identical are treated as duplicates. Names, dates and folders don't matter, and similar-but-different files such as two edits of one photo aren't flagged. Cloud accounts are compared using the provider's own content fingerprints, so nothing is downloaded.","crumbs":[{"name":"Home","path":"/"},{"name":"FAQ","path":"/faq/"},{"name":"Duplicate files","path":"/faq/duplicates/"},{"name":"How does Storage Studio decide that two files are duplicates?","path":"/faq/duplicates/how-does-storage-studio-decide-two-files-are-duplicates"}],"jsonld":{"@context":"https://schema.org","@type":"FAQPage","url":"https://storagestudio.us/faq/duplicates/how-does-storage-studio-decide-two-files-are-duplicates","inLanguage":"en","dateModified":"2026-10-01","mainEntity":[{"@type":"Question","name":"How does Storage Studio decide that two files are duplicates?","alternateName":["Does the duplicate finder compare file names or contents?","How accurate is Storage Studio's duplicate detection?","Are duplicates matched by name or by content?","How do you know two files are identical?","duplicate detection by content mac","Could it mark two different files as duplicates?","What counts as a duplicate in Storage Studio?"],"acceptedAnswer":{"@type":"Answer","text":"Two files count as duplicates only when their full content is identical. Names, dates and folders don't matter — a file called \"Invoice.pdf\" in Downloads and \"March invoice.pdf\" in Documents are a duplicate set if their contents match exactly, while two files with the same name but different contents are not.\n\nWe don't publish the details of how files are compared, but here's what it means for you: on your Mac the whole content of each candidate is checked, not just the start of the file or its size, so a set only appears when the copies really are the same. In cloud accounts, Storage Studio uses the content fingerprints your provider already keeps for each file, so nothing has to be downloaded.\n\nSimilar-looking files — two edits of the same photo, or a song in two formats — aren't exact copies, so they're not shown.","url":"https://storagestudio.us/faq/duplicates/how-does-storage-studio-decide-two-files-are-duplicates"}}]},"fragment":"<div class=\"wrap fl-wrap\"><div class=\"fl-layout\"><aside class=\"fl-side\" aria-label=\"FAQ topics\"><details open><summary>All topics</summary><ul class=\"fl-tree\"><li><a href=\"/faq/getting-started/\">Getting started</a> <span>70</span></li><li><a href=\"/faq/freeing-space/\">Freeing up space</a> <span>182</span></li><li><a href=\"/faq/moving-folders/\">Moving folders</a> <span>144</span></li><li><a href=\"/faq/apps/\">Apps</a> <span>146</span></li><li><a href=\"/faq/external-drives/\">External drives</a> <span>169</span></li><li><a href=\"/faq/finder-location/\">Finding things in Finder</a> <span>70</span></li><li><a href=\"/faq/cloud-accounts/\">Cloud accounts</a> <span>158</span></li><li><a href=\"/faq/icloud/\">iCloud &amp; iCloud Photos</a> <span>168</span></li><li><a href=\"/faq/data-transfers/\">Data Transfers</a> <span>119</span></li><li><a href=\"/faq/backups/\">Backups &amp; restore points</a> <span>126</span></li><li><a href=\"/faq/delta-drive/\">Delta Drive, Delta Trust &amp; My Drive</a> <span>125</span></li><li><a href=\"/faq/bridge-devices/\">Bridge &amp; your devices</a> <span>111</span></li><li class=\"fl-open\"><a href=\"/faq/duplicates/\" aria-current=\"true\">Duplicate files</a> <span>74</span><ul><li class=\"fl-on\"><a href=\"/faq/duplicates/#basics\">Duplicates basics</a> <span>9</span></li><li><a href=\"/faq/duplicates/#where-it-looks\">Where it looks and what it skips</a> <span>9</span></li><li><a href=\"/faq/duplicates/#scanning\">Scanning and Auto-scan</a> <span>14</span></li><li><a href=\"/faq/duplicates/#choosing-what-to-keep\">Choosing which copy to keep</a> <span>7</span></li><li><a href=\"/faq/duplicates/#removing-and-restoring\">Removing and restoring duplicates</a> <span>9</span></li><li><a href=\"/faq/duplicates/#icloud-duplicates\">Duplicates in iCloud Drive</a> <span>3</span></li><li><a href=\"/faq/duplicates/#cloud-duplicates\">Duplicates in cloud accounts</a> <span>12</span></li><li><a href=\"/faq/duplicates/#smart-care\">Duplicates and Smart Care</a> <span>3</span></li><li><a href=\"/faq/duplicates/#troubleshooting\">Duplicate messages and problems</a> <span>8</span></li></ul></li><li><a href=\"/faq/junk-yard/\">Junk Yard</a> <span>113</span></li><li><a href=\"/faq/tuhi-assistant/\">Tuhi, your storage assistant</a> <span>105</span></li><li><a href=\"/faq/settings/\">Settings &amp; keep-time</a> <span>88</span></li><li><a href=\"/faq/performance-battery/\">Performance &amp; battery</a> <span>62</span></li><li><a href=\"/faq/privacy-safety/\">Privacy &amp; safety</a> <span>85</span></li><li><a href=\"/faq/licensing-payments/\">Licensing &amp; payments</a> <span>131</span></li><li><a href=\"/faq/troubleshooting/\">Troubleshooting &amp; messages</a> <span>180</span></li><li><a href=\"/faq/comparisons/\">Comparisons &amp; alternatives</a> <span>75</span></li><li><a href=\"/faq/mac-storage-basics/\">Mac storage basics</a> <span>315</span></li></ul></details></aside><div class=\"fl-main\"><nav class=\"fl-crumbs\" aria-label=\"Breadcrumb\"><ol><li><a href=\"/\">Home</a></li><li><a href=\"/faq/\">FAQ</a></li><li><a href=\"/faq/duplicates/\">Duplicate files</a></li><li aria-current=\"page\">How does Storage Studio decide that two files are duplicates?</li></ol></nav>\n<form class=\"fl-search\" action=\"/faq/search\" method=\"get\" role=\"search\" data-fl-search>\n<label class=\"fl-visually-hidden\" for=\"fl-q\">Search the FAQ</label>\n<input id=\"fl-q\" type=\"search\" name=\"q\" value=\"\" placeholder=\"Search 2,816 questions…\" autocomplete=\"off\" spellcheck=\"false\">\n<button type=\"submit\">Search</button>\n<div class=\"fl-suggest\" role=\"listbox\" hidden></div>\n</form>\n<article class=\"fl-entry\">\n<p class=\"eyebrow fl-eyebrow\"><a href=\"/faq/duplicates/\">Duplicate files</a> · <a href=\"/faq/duplicates/#basics\">Duplicates basics</a></p>\n<h1>How does Storage Studio decide that two files are duplicates?</h1>\n<p class=\"fl-short\"><strong>Short answer:</strong> Only files whose full content is identical are treated as duplicates. Names, dates and folders don&#39;t matter, and similar-but-different files such as two edits of one photo aren&#39;t flagged. Cloud accounts are compared using the provider&#39;s own content fingerprints, so nothing is downloaded.</p>\n<div class=\"fl-answer\"><p>Two files count as duplicates only when their full content is identical. Names, dates and folders don&#39;t matter — a file called &quot;Invoice.pdf&quot; in Downloads and &quot;March invoice.pdf&quot; in Documents are a duplicate set if their contents match exactly, while two files with the same name but different contents are not.</p>\n<p>We don&#39;t publish the details of how files are compared, but here&#39;s what it means for you: on your Mac the whole content of each candidate is checked, not just the start of the file or its size, so a set only appears when the copies really are the same. In cloud accounts, Storage Studio uses the content fingerprints your provider already keeps for each file, so nothing has to be downloaded.</p>\n<p>Similar-looking files — two edits of the same photo, or a song in two formats — aren&#39;t exact copies, so they&#39;re not shown.</p></div>\n\n<p class=\"fl-meta\">Last reviewed <time datetime=\"2026-10-01\">October 1, 2026</time></p>\n\n<section class=\"fl-related\"><h2>Related questions</h2><ul><li><a href=\"/faq/duplicates/does-it-find-similar-photos-or-only-exact-copies\">Does Storage Studio find similar photos, or only exact copies?</a></li><li><a href=\"/faq/duplicates/do-files-with-the-same-name-count-as-duplicates\">Do files with the same name count as duplicates?</a></li><li><a href=\"/faq/duplicates/does-duplicate-scanning-download-my-cloud-files\">Does checking a cloud account for duplicates download my files?</a></li></ul></section>\n<p class=\"fl-formats\">Also available as <a href=\"/faq/duplicates/how-does-storage-studio-decide-two-files-are-duplicates.md\">Markdown</a> and <a href=\"/faq/duplicates/how-does-storage-studio-decide-two-files-are-duplicates.json\">JSON</a>.</p>\n</article></div></div></div>"}