DuoBolt
Windows 10 & 11 · x64 & ARM64, both native

A duplicate file finder for Windows that reads contents, not names

DuoBolt compares files byte-for-byte with BLAKE3 — no name patterns, no size guessing, no partial checksums. It runs natively on x64 and on ARM64, so a Copilot+ PC gets a real build rather than an emulated one, and nothing is removed until you have seen exactly what it found.

Free to use · One-time purchase from $34.99 · 2 seats · 30-day refund
v2.1.0 · macOS & Windows · Docs
DuoBolt running on Windows 11: duplicate scan results with a File Type Distribution donut over 5,376 groups and 9.9 GiB reclaimable, and one group expanded to show two byte-for-byte identical copies of the same painting under C:\Users\Public\Pictures, one in a folder ending Copy

Emulated software is the Windows tax nobody mentions

Most desktop apps on an ARM Windows machine are x64 binaries being translated instruction by instruction, and a duplicate scan is exactly the workload that punishes — hashing is CPU-bound and runs across every thread you have. DuoBolt ships a real ARM64 build, so those threads do the work rather than the translation. On x64 the same engine, the same BLAKE3 hashing and the same grouping produce the same duplicate groups a Mac would return, because it is the same engine.

Native on both Windows chips

x64 and ARM64 builds, each running natively — nothing is emulated. On a Snapdragon X or any Copilot+ PC that means full speed instead of the translation-layer tax most desktop software still pays there.

Content-based matching

Every candidate is fully hashed with BLAKE3 and grouped only when contents match exactly. Identical files renamed across folders are still found; different files sharing a name are never confused for each other.

Four ways out, and you pick

Move to the Recycle Bin, move to an Archive folder, copy somewhere else, or delete outright. Only the last one is final, and it says so — and every operation is written to a history you can restore from.

Local drives, mapped drives, UNC paths

Internal NVMe and SATA, USB externals, SD cards, mapped drive letters and raw UNC paths to a NAS or file server — all scan the same way, and duplicates are found across roots as well as inside them.

How a duplicate is proven

Four steps from a folder pick to a confirmed cleanup. The scan is entirely local: no account, no upload, nothing about your files leaves the PC.

  1. Step

    Add folders or drives

    Drop in any combination of local folders, mapped drives and UNC paths. Exclude anything you want left alone, set a size floor, and every scan root is walked in parallel.

  2. Step

    Hash with BLAKE3

    A head-and-tail prehash drops the non-matches first; whatever survives is fully hashed with multi-core BLAKE3 across every available thread.

  3. Step

    Review every match

    Each group shows full paths, sizes and previews. Use the bulk-select rules or pick by hand — nothing is ticked for you without an explicit choice.

  4. Step

    Choose what happens

    Recycle Bin, Archive folder, a copy elsewhere, or a permanent delete. Nothing moves until you confirm it, and the operations history records what was touched either way.

Windows duplicate finder FAQ

Does DuoBolt run natively on ARM Windows?
Yes. There is a real ARM64 build, not an x64 binary under emulation, so a Snapdragon X or any other Copilot+ PC runs it at full speed. Most duplicate finders still ship x64 only and rely on Windows to translate them, which costs both throughput and battery.
Which versions of Windows are supported?
Windows 10 and Windows 11, on x64 and ARM64. The installer is code-signed and needs no administrator privileges to scan your own folders.
Does DuoBolt rely on file names or sizes to detect duplicates?
No. A full-content BLAKE3 hash is computed before two files are ever called identical. Names, timestamps and sizes are shown for context and are never used to decide a match.
Will DuoBolt delete anything without me confirming?
Never. Nothing is selected by default, and nothing is removed until you confirm it on a review screen showing full paths, sizes and previews. You then pick between the Recycle Bin, an Archive folder, a copy elsewhere, or deleting outright.
Can it scan a mapped network drive or a NAS share?
Yes. Mapped drive letters, UNC paths and mounted SMB shares all work, and nothing is installed on the NAS itself. Large network scans benefit from raising the size floor so the walk skips the thousands of tiny files that dominate a share.
Why does DuoBolt skip my iPhone photos on Windows?
Because Windows cannot open HEIC on its own. Grouping look-alike photos means decoding the picture, and that needs a free Microsoft Store add-on: HEIF Image Extension, which covers HEIC and HEIF. AVIF is a separate format with its own free add-on, AV1 Video Extension — worth installing if you have AVIF images, though an iPhone does not produce them. Install what applies and the library groups normally. Finding byte-for-byte duplicate files is unaffected either way: that path never opens an image, it hashes the bytes. HEIF Image Extension → AV1 Video Extension →
Does DuoBolt detect similar images or near-duplicates?
Yes, on a second engine that is kept deliberately separate. The duplicate finder matches only when two files are byte-for-byte identical, and it will never call anything else a duplicate. Near-identical images — bursts, retakes, a RAW and the JPEG exported from it — are grouped by what the picture shows and ranked rather than declared identical, and the results label which verdict you are looking at.