AngelCOPY

Replace Windows Explorer's slow, single-threaded copy with robocopy /MT:64 throughput — integrated so normal actions trigger it.

• Right-drag files onto a folder or drive → Copy here FAST / Move here FAST.
• Copy / paste via right-click Copy FAST / Paste FAST.
• A native progress dialog with a throughput chart — progress band and speed curve in one control, like Windows' own copy dialog — plus current file, time remaining and items remaining. Follows the light/dark system theme. Errors are listed in the dialog.
• A conflict dialog asks before overwriting anything (Replace all / Only if newer / Skip existing / Cancel).
• Delete FAST — right-click → permanent delete, ~3x faster than Explorer. Always asks first.
• Installs machine-wide; uninstalls cleanly and restores stock behavior.

Why is nothing invisible? (Ctrl+V, left-drag)

Windows offers no supported way to replace Explorer's copy for either Ctrl+V or a plain left-drag:

• Ctrl+V — Explorer handles paste internally; there is no shell extension point for it.
• Left-drag onto a folder — the shell serves folder drops from its own internal IDropTarget. A DropHandler registered under Directory\shellex\DropHandler is never consulted (tests\test_droptarget.cpp proves this by asking the shell the same question Explorer does). Stock Windows registers drop handlers only for exefile, lnkfile and CompressedFolder.

Intercepting either would mean hooking Explorer from the inside (a keyboard hook, or patching IFileOperation in explorer.exe) — fragile, antivirus-flagged, and liable to break with Windows updates. AngelCOPY deliberately doesn't.

What is supported, and what AngelCOPY uses:

Action	Extension point
Right-drag → "Copy here FAST"	shellex\DragDropHandlers (as used by 7-Zip, WinMerge)
Right-click → Copy / Paste / Delete FAST	shellex\ContextMenuHandlers

Language

The UI follows the system UI language: German if Windows is German, English otherwise. Menu entries read <verb> FAST (AngelCOPY) — verb first, like the shell's own items, with FAST keeping them apart from the native entry next to them. All strings live in shared\Localize.*; adding a language means adding one table (/utf-8 is required to build).

Architecture

AngelCopyShell.dll   x64 in-proc COM  — Explorer integration (thin)
AngelCopyRunner.exe  x64              — spawns robocopy /MT:64, shows progress
AngelCOPY-Setup.exe  Inno Setup       — install / register / uninstall

The DLL stays thin: all real work runs in the separate AngelCopyRunner.exe, so a hang or crash during a transfer never destabilizes Explorer.

Drag&drop handler (AngelCopyShell/DragDropHandler.cpp) is an IShellExtInit + IContextMenu handler registered under Directory\shellex\DragDropHandlers and Drive\.... On a right-drag the shell hands it both halves of the operation — pidlFolder is the folder the items were dropped on, pdtobj the dragged items — and it offers Copy/Move here FAST.

Context menu (AngelCopyShell/ContextMenu.cpp) is a classic IContextMenu + IShellExtInit handler: Copy FAST on a selection puts the items on the clipboard; Paste FAST on a folder / background reads the clipboard and runs the transfer; Delete FAST prompts, then deletes.

Runner (AngelCopyRunner/) turns a request into robocopy jobs: robocopy "<src>" "<dst>" /MT:64 /E /COPY:DAT /R:2 /W:2 /XJ for folders, a file-filter form for loose files, /MOVE (or /MOV) for moves.

Build

Requires Visual Studio 2022 with the Desktop development with C++ (x64) workload. From a normal command prompt:

build.bat

Produces dist\AngelCopyShell.dll and dist\AngelCopyRunner.exe.

To build the installer (requires Inno Setup 6):

"C:\Program Files (x86)\Inno Setup 6\ISCC.exe" installer\AngelCOPY.iss

Produces dist\AngelCOPY-Setup.exe.

Install

Installer (recommended): run dist\AngelCOPY-Setup.exe (elevates, registers the shell extension, restarts Explorer). Uninstall via Apps & features — it unregisters, removes its keys, and restarts Explorer.

Dev scripts (no installer): after build.bat, right-click → Run as administrator:

scripts\install-dev.bat      register dist DLL + restart Explorer
scripts\uninstall-dev.bat    unregister + restart Explorer

Verify it works

1. Runner alone (no install needed): dist\AngelCopyRunner.exe copy D:\dest C:\some\bigfolder — confirm files land and a robocopy.exe runs with /MT:64 (Task Manager / wmic process).
2. Right-drag (after install): drag a folder onto another folder with the right mouse button, release → the menu contains Copy here FAST / Move here FAST (German Windows: Hierher kopieren FAST). Pick one; Task Manager shows robocopy.exe working.
3. Context menu: right-click files → Copy FAST; right-click a folder's empty space → Paste FAST; right-click files → Delete FAST.
4. COM smoke test (no registry/Explorer): tests\test_load.cpp loads the DLL and checks every interface.
5. Drop-target reality check: tests\test_droptarget.cpp asks the shell for a folder's IDropTarget the way Explorer does. It documents why a left drag cannot be intercepted — the object returned is never ours.

What happens when files already exist?

A pre-scan compares every source file with the destination. Identical files (same size, mtime within 2s) are skipped by robocopy and are not treated as conflicts. If files would really be overwritten, AngelCOPY asks first:

Choice	robocopy flags	Effect
Replace all	(default)	Overwrite every differing file
Only if newer	/XO	Never let an older source overwrite a newer destination
Skip existing	/XC /XN /XO	Only copy files not already there
Cancel	—	Nothing is touched

Existing destination folders are merged, never replaced, and files that exist only at the destination are always left alone (no purge/mirror).

Delete FAST

Right-click → Delete FAST (AngelCOPY). It always shows a confirmation with the file count and size; Cancel is the default button.

Permanent only — it does not use the Recycle Bin and cannot be undone.

Why permanent-only, and why not robocopy? Both were measured on 5000 files:

Method	Time
Explorer engine, permanent (SHFileOperation)	1836–2962 ms
Explorer engine → Recycle Bin	2473 ms
robocopy /MIR /MT:64 (the "fast delete" trick)	908 ms
robocopy /MIR /MT:1	919 ms
AngelCOPY Delete FAST	580 ms

/MT:64 and /MT:1 are the same: robocopy does not parallelize deletion, so the famous trick buys nothing over a plain delete. Deletion is bound by NTFS metadata, not throughput — threads gain ~20% at best. The ~3x win is simply from not paying Explorer's per-item shell overhead. And the Recycle Bin can only be driven through Explorer's own engine, so there is no speed to gain there — which is why that option isn't offered.

Junctions and symlinks are removed, never followed into. Read-only files are deleted. Long paths (beyond MAX_PATH) work.

Limitations / notes

• x64 only. Modern Explorer is 64-bit; the handler must match.
• Move onto an identical file: robocopy only deletes source files it actually copied, so a file already present identically at the destination is neither copied nor deleted from the source — a move can leave part of the source behind.
• Windows 11 context menu: the classic menu (Copy/Paste FAST) appears under "Show more options" (or Shift+F10). Putting entries in the main Win11 menu requires shipping an MSIX/IExplorerCommand package — out of scope for this personal-use, unsigned build.
• Move semantics: on a fast-path drop AngelCOPY reports DROPEFFECT_COPY and lets robocopy /MOVE delete the source itself — this prevents Explorer from deleting source files while robocopy is still reading them.
• Unsigned: SmartScreen/Defender may warn on AngelCOPY-Setup.exe. Expected for an unsigned personal build.
• Updating the DLL: Explorer keeps it loaded; the installer restarts Explorer so a new build takes effect (and schedules locked-file cleanup on reboot).

Layout

AngelCopyRunner/     main.cpp, Robocopy.{h,cpp}      — the worker exe
AngelCopyShell/      dllmain, Common, Guids,          — the COM shell DLL
                     DragDropHandler, ContextMenu, Register, .def
installer/           AngelCOPY.iss                    — Inno Setup script
scripts/             install-dev.bat, uninstall-dev.bat
tests/               test_load.cpp                    — COM smoke test
build.bat                                             — compiles both artifacts