[mikecerisano]

Check could terminate the app when selecting a folder with a multi-file MHL or JSON report. Saved-checksum discovery treated each file's record URL as unique. Collect each contributing record once while preserving per-file evidence, newest-record selection and corruption detection. A two-file MHL/JSON regression reproduces the original fatal traps.

Also clarify missing/extra comparison results and existing hidden macOS companion conflicts, add privacy-safe comparison phases/counts/outcomes and correctly correlate cancellation, and stop offering Eject for internal folders. No overwrite, readback or safety-verdict protections are relaxed.

Validation performed locally (CI is not the acceptance gate):

• Full Mac app suite after the final fix: 1,063 passed, eight skipped, zero failures.
• Final serial Release engine suite: 114 XCTest cases (15 skips), zero failures; 132 Swift Testing tests, zero failures. An earlier parallel run hit three timing deadlines and stalled; retained separately, no weakened assertions.
• Final Mac/iOS Simulator Release builds passed; rebuilt Developer ID review app successfully checked the formerly crashing multi-file MHL (34 intact files), then compared folders and exported correlated, private-name-free diagnostics.
• Mounted HFS+ source to exFAT + case-sensitive APFS: initial and existing-file transfers, Standard, MHL and reports; 52 rows each.
• Signed-app transfer to exFAT + APFS: 34 files including a 1 GiB synthetic file, 68 verified copies; independent SHA-256 and complete MHL inventories; PDF/CSV/JSON reports.
• Signed-app reporting cancellation saved an interrupted unsafe verdict, logged menu cancellation and preserved all 2,000 source and 4,005 existing destination files.
• New cancellation correlation and internal-eject tests were verified failing without their guards, then passing restored.
• Earlier iPhone/iPad comparison snapshots passed and were visually inspected. No physical-device picker test claimed.

The Mac test-host loader stall was resolved by using derived data outside Desktop, with no signing/privacy changes. Earlier failed/stalled attempts are documented separately.

Keep #8 open: the supplied Sony XML/BIM files remain private and local. The Check crash is confirmed; the reporter's later Copy & Verify failure is not reproduced. No original MOV footage or physical Sony reader was tested. No release/version change or publication in this PR.