DoubleKiller vs Dup Detector

DoubleKiller is a Windows utility that finds duplicate files in directories, on complete drives or on computers in Network Neighborhood. It can compare files using any combination of name, size, modification date and content. Scans can exclude files by name, type, attributes or size, and the results list lets users choose files to delete or move to another directory. Results can also be exported to a text file. The program is a standalone executable that can be extracted and run without installation; its maker says it does not change the system without prior permission. The free version is for private use and allows unlimited folder and file counts, but individual files are limited to 2 GB and commercial use is not permitted. DoubleKiller Pro adds a multilingual interface, advanced comparison options, saved and reloadable result lists, and command-line automation. The download page lists version 1.6.2.82 dated 2007-07-07, and the maker says development is paused. The listed paid starting price is $19.95 one-time.

Dup Detector is a free, open-source desktop application for finding duplicate files and reclaiming storage space. It runs on Linux, macOS, and Windows. Smart hashing compares file sizes first, then partial content, and performs full content hashing when needed. The maker says smart hashing can scan 10,000 or more files per second. Multithreaded scanning is supported, and the app describes its memory footprint as minimal. Dup Detector identifies duplicates but does not remove them automatically, so users decide which files to keep or delete. The maker says the code is fully open source and welcomes inspection and contributions. It states that the app has no analytics, telemetry, or data collection. The Free plan costs nothing, is available forever, and includes cross-platform use. GitHub issues and Discord provide support and feedback channels.