Build

Use an x64 Native Tools Command Prompt for Visual Studio with the C++ tools and a Windows SDK installed. Change to the extracted attachment directory and run:

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

No Rust toolchain, external library, network connection, remote server, or driver modification is needed.

Run

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

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

The selected directory must not already exist. If the example location is not writable by the current user, choose another writable location. Administrator privileges are not requested by the program.

The program creates three isolated roots (batch, single, reverse), each with two synthetic 4096-byte placeholders. It queries metadata only; it does not download file contents. All FileIdentity blobs are 512 bytes and are generated deterministically by the source.

Interpretation

REPRODUCED=yes means only the original two-entry batch produced one error 363, and both control cases were healthy.
REPRODUCED=no means this exact three-case result was not observed; retain the full output and OS/driver versions for comparison.
Exit code 0 means the experiment completed and cleanup succeeded. It does not mean Windows was free of the defect.
Other API errors stop the experiment with a nonzero exit code.

Cleanup

The program automatically repairs corrupt synthetic FILES using a single-entry CF_PLACEHOLDER_CREATE_FLAG_SUPERSEDE call, disconnects and unregisters each test root, and deletes its own files and directories.

It never recursively deletes arbitrary contents, does not touch existing sync roots, and refuses to reuse an existing test parent directory. The supersede step discards synthetic test data; it is not a recovery recipe for user files. No corrupt-directory case is included.

CLEANUP=OK confirms that cleanup succeeded. If CLEANUP=INCOMPLETE appears, retain the output and inspect only the explicitly chosen test directory. Do not use any system-wide filter changes as part of this reproducer.

When recording with Feedback Hub

Build first. Start the optional recording, run the command once, then stop recording. Attach the source, output, and report. It is not necessary to reproduce against a real sync directory.