Save As destination collisions now explain that existing files are protected
and offer clear recovery: choose a fresh source directory, or use Save All at
the current entry. Genuine observed external edits keep their distinct
external-change diagnosis. This preview includes the prior compact diagram
controls and contextual Help; model/source/history semantics and REST contracts
are unchanged.

Download the Windows x86-64 Studio ZIP and checksum, verify SHA256 and extract
the whole folder. Launch `arcadia-studio.exe`, keeping `libunwind.dll` beside both
executables. Read `START-HERE.txt` and the attached `VALIDATION.md`. Copy a complete
example before editing; Save As copies model source with existing include paths,
so companion/external artifacts need separate copying. The optional REST server,
examples, offline guide and notices are included.

Desktop source **0e83157e09d52e6152df91208e41693b62da2d46**; packaged documentation
**ef28f1784efe6717b0ca72c0eb3c97bc30ebfe47**. The server is the unchanged released
715 artifact with recovered original build provenance and fresh tests of this
bundle's selected runtime. Both binaries use the dev/unoptimized profile;
packaging did not rebuild them.

Verified: 29 targeted desktop save checks, formatting, strict Clippy and matching
GUI build; exact archive/extraction/notice/documentation identities; fresh
independent source/artifact/native/REST/claims review. Two actual extracted
desktop sessions exercise Apply, accurate refusal and recovery, genuine external
edit protection, fresh Save As, reopen and no-op Save All. Complete 37-file byte
oracles and full 30-source-file parsed Projects allow only the declared Activity
name change. Both desktop processes exit 0 with empty logs and all 565 package
files unchanged. Fresh server testing passes 23 scoped assertions, including exact
OpenAPI, Unicode/CRLF, stale 412 and acknowledged-write persistence after owned
forced restart. No new full-suite or graceful/power-loss claim is made.

ZIP: **34,191,561 bytes**, SHA256
`8b4e353e075f22350a07794ee47a02cf85725501223299cf367134aa1f5b63b7`.

This is an unfinished scoped Windows development prerelease, not the complete
OA/SA release or separately owned follow-up union. Dense diagrams, remaining
Scenario group adapters, quantities/calculations/constraints, maintained
libraries and broad accessibility/DPI remain unfinished. Native testing used
one existing account/machine at 1442×932 with system-only child PATH. The footer's
complete guidance was read with a pointer tooltip; keyboard-only access remains
untested. Linux/WSL remains user-deferred. Existing releases/tags remain unchanged.

[Exact validation, independent review, preserved evidence and build/run instructions](http://217.177.34.108:3000/sorokin.oleg.edu/ARCADIA-Studio/src/commit/e144e32e9984477a258759a9dcc75f6e499fc224/harness/release-save-diagnostics-validation-20261001.md)
identify the separate source/build/package scopes. This tag points to the
reviewed evidence-only checkpoint **e144e32e9984477a258759a9dcc75f6e499fc224**, with production inputs unchanged.