Build

Save repro.cpp.txt as repro.cpp. Use an x64 Native Tools Command Prompt for Visual Studio with the C++ tools and Windows SDK (including C++/WinRT headers):

  cl /nologo /std:c++17 /EHsc /W4 repro.cpp /Fe:repro.exe

Tested with Visual Studio 2022 and Windows SDK 10.0.26100.0. The libraries are specified by pragma comment directives in the source. No Rust toolchain, third-party dependency, network connection, remote server, or debugger is needed.

Run

Choose a NEW directory on a writable local NTFS volume, outside existing sync roots:

  repro.exe C:\CfShellDeleteRepro > actual-output.txt 2>&1

Use another writable path if needed. The parent directory must exist, but CfShellDeleteRepro itself must not exist. The program does not request administrator privileges.

The program creates eight isolated registrations: four cases for each of the FULL and ALWAYS_FULL population policies. Each root contains nine synthetic directories and two eight-byte files. A child process performs permanent Shell deletion. The parent independently checks what remains after the child exits.

The --delete mode is internal to that child process; use the ordinary command above.

Interpretation

REPRODUCED=yes means the three controls deleted completely and the Shell-registered/cloud-directory/offline-file case left exactly the five documented ancestors under both population policies.

REPRODUCED=no means this exact pattern was not observed. Keep the full output and Windows/DLL/driver versions for comparison.

Exit code 0 means the experiment and cleanup completed. It does not mean Windows deleted every tree successfully. Unexpected API failures or cancellations stop the experiment with a nonzero exit code.

Cleanup

The program disconnects and unregisters its test roots, then removes only the fixed synthetic file and directory paths it created. It does not recursively delete arbitrary contents or modify existing sync roots.

CLEANUP=OK confirms cleanup. If CLEANUP=INCOMPLETE appears, retain the output and inspect only the chosen test directory. No filter detachment, reparse-data editing, or driver changes are part of this experiment.

Posting to Q&A

Suggested category: Windows development | Windows API - Win32.
Use the title and body in report.txt, and attach repro.cpp.txt, actual-output.txt,
run-instructions.txt, and optionally trace-excerpt.txt.

The report notes that Feedback Hub is unavailable on the tested LTSC installation
and requests escalation or a web-based defect-reporting route.