From 7712e3185ee15c8cac4ac001a7cc7de89c9fc901 Mon Sep 17 00:00:00 2001
From: N0zoM1z0 <161784452+N0zoM1z0@users.noreply.github.com>
Date: Wed, 11 Nov 2026 01:15:46 +0000
Subject: [PATCH] fix(ntfs): retain incomplete coverage alongside fixup
 mismatches

Co-authored-by: gensokyo-dev <342580529+gensokyo-dev@users.noreply.github.com>
---
 src/domain/windows/ntfsMft.test.ts | 14 ++++++++++++++
 src/domain/windows/ntfsMft.ts      |  5 ++++-
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/src/domain/windows/ntfsMft.test.ts b/src/domain/windows/ntfsMft.test.ts
index 8706d3fc3c..9ed0712657 100644
--- a/src/domain/windows/ntfsMft.test.ts
+++ b/src/domain/windows/ntfsMft.test.ts
@@ -239,6 +239,20 @@ describe("MFT fixup coverage", () => {
     },
   );
 
+  it("counts uncovered sectors independently of a mismatched trailer", () => {
+    const parsed = parseMftImage(
+      recordOf({ recordBytes: 4096, usaEntries: 3, corruptSector: 0 }),
+    );
+    if (!parsed.ok) throw new Error(parsed.error.message);
+    expect(parsed.value.metadata).toMatchObject({
+      fixup_mismatch_count: 1,
+      fixup_unverified_record_count: 1,
+    });
+    expect(parsed.value.limitations.join(" ")).toContain(
+      "invalid or incomplete",
+    );
+  });
+
   it("reports an array that covers fewer sectors than the record has", () => {
     // A 4 KiB record holds eight sectors; a three-entry array leaves five unverified.
     const parsed = parseMftImage(
diff --git a/src/domain/windows/ntfsMft.ts b/src/domain/windows/ntfsMft.ts
index 8599c671f1..bc901e5e6d 100644
--- a/src/domain/windows/ntfsMft.ts
+++ b/src/domain/windows/ntfsMft.ts
@@ -284,7 +284,10 @@ const scanMft = (
     if (record.directory) directoryCount += 1;
     if (record.baseRecordReference !== null) extensionCount += 1;
     if (record.fixups.mismatchSector !== null) mismatchCount += 1;
-    else if (record.fixups.verifiedSectors < recordBytes / FIXUP_SECTOR_BYTES)
+    if (
+      record.fixups.malformed ||
+      record.fixups.coveredSectors < recordBytes / FIXUP_SECTOR_BYTES
+    )
       unverifiedCount += 1;
     if (!record.extentValid) {
       invalidExtents += 1;