How to…?

Drag a folder on a Duplicarius window, the app icon in Finder or Dock, or pick with the ‘Open’ command in the ‘File’ menu. Then click ‘Find Duplicates’.
Duplicarius will scan the selected folder, and optionally its subfolders, for duplicate files. It lists every group of duplicates in the left list. Selecting a group of duplicates in the left list will show the individual files, and some file information, in the right list.

Which files are considered to be duplicates

Duplicarius looks at the data in a file, and, if existing, the data in the resource fork of the file. It calculates a checksum (SHA256) of this data, and then compares the checksums. Duplicarius does not take into account metadata like creation and modification dates, owner, group and permissions, or extended attributes.

Handling of some edge cases can be configured in the preferences. When in doubt, leave these options at their default settings (all enabled).


The ‘Toggle’ command behaves slightly differently depending on which list is focused. When used in the left list, it will either unflag all files of the group, or select all but the first one (like auto flagging, but just for the selected group).
When used in the right list, it will toggle the selected file in the same way like directly clicking the checkbox would.

Auto Flag

Automatic flagging will first unflag all currently flagged files, and then flag all but the first file based on ordering by the following rules (customizable in Version 2.4 and later):

Duplicarius will not modify files

Duplicarius will never change the contents of files, and it will not delete them - it will just move them to the trash or folder, when asked to.
Please note that some versions of macOS have a bug that reports a file couldn’t be written when in fact, due to insufficient permissions, it couldn’t be read. Again: Duplicarius will never modify the content of your files.

I see a warning symbol

A warning symbol indicates a situation that is not fatal, but may result in an outcome that is not intended. Hover the cursor over the symbol or click it to see what is causing this.