Duplicate Detection

OffShoot will automatically detect duplicates when copying data into an existing folder structure. A file will not be copied when all of these conditions are met:

• A file with an identical name exists in the folder where the copy will end up

• That file has the same file size

• That file has the same modification date

When a file with an identical name already exists on the destination path, but has a different byte size and/or modification date, it will be copied using a counter following Finder and Explorer's duplicate naming conventions: B002C006_180327_R1ZA.mov becomes B002C006_180327_R1ZA 2.mov.

Skip duplicate-detection checks

In some workflows, duplicate detection can’t rely on a file’s modification date or file size. In those cases, you can skip the modification date or file size check.

macOS

Requires OffShoot 26.1.2 or newer.

1. Open Terminal.

2. Paste the command below, then press Return:

   1. skip modification date check

      defaults write nl.syncfactory.Hedge.Mac SFIDefaultsSkipDuplicateDetectModificationDateCheck -bool true

   2. skip file size check

      defaults write nl.syncfactory.Hedge.Mac SFIDefaultsSkipDuplicateDetectFileSizeCheck -bool true

To undo this change:

1. Open Terminal.

2. Paste the command below, then press Return:

   defaults delete nl.syncfactory.Hedge.Mac SFIDefaultsSkipDuplicateDetectModificationDateCheck

   defaults delete nl.syncfactory.Hedge.Mac SFIDefaultsSkipDuplicateDetectFileSizeCheck

Logging

Skipped files will be logged in the Transfer Log, under the section:

-- Skipped files (already on destination) --

Duplicates that do not match all criteria are logged as such:

-- Transferred files -- #1: B002C006_180327_R1ZA.mov path: XDROOT/CLIPS/B002C006_180327_R1ZA 2.mov

Finding duplicates without copying

If an identical file exists in a different folder on your destination, the source file will be copied. If you are looking for a way to find duplicates on an existing drive, have a look at Duplicate Detective or Gemini.