diff --git a/.github/workflows/release.yaml b/.github/workflows/release.yaml
index 7e932b9..ff3f272 100644
--- a/.github/workflows/release.yaml
+++ b/.github/workflows/release.yaml
@@ -634,33 +634,35 @@ jobs:
 
           SIGNED_COUNT=0
 
-          # Find all SBOM files generated by GoReleaser (syft)
-          # All files are in dist root (MSI files flattened by previous step)
-          for sbom in "${CALLER_DIST}"/*.sbom.json; do
-            [ -f "$sbom" ] || continue
-
-            SBOM_BASENAME=$(basename "$sbom")
-            ARCHIVE_NAME="${SBOM_BASENAME%.sbom.json}"
-            ARCHIVE="${CALLER_DIST}/${ARCHIVE_NAME}"
+          # Require every Windows release artifact to have an SPDX SBOM.
+          # MSI files are flattened to dist root by the previous step.
+          for artifact in "${CALLER_DIST}"/*.zip "${CALLER_DIST}"/*.msi; do
+            [ -f "$artifact" ] || continue
+            [[ "$artifact" == *checksums* ]] && continue
 
-            if [ ! -f "$ARCHIVE" ]; then
-              echo "::error::Could not find archive for SBOM: $sbom (expected: $ARCHIVE)"
+            SBOM="${artifact}.sbom.json"
+            if [ ! -f "$SBOM" ]; then
+              echo "::error::Missing SBOM for artifact: $(basename "$artifact") (expected: $SBOM)"
               exit 1
             fi
 
-            echo "Signing SBOM for: $(basename "$ARCHIVE")"
+            echo "Signing SBOM for: $(basename "$artifact")"
             cosign attest-blob \
               --yes \
-              --predicate "$sbom" \
+              --predicate "$SBOM" \
               --type https://spdx.dev/Document \
-              --bundle "${ARCHIVE}.sbom.sigstore.json" \
-              "$ARCHIVE" > /dev/null
-            echo "✅ Created $(basename "$ARCHIVE").sbom.sigstore.json"
+              --bundle "${artifact}.sbom.sigstore.json" \
+              "$artifact" > /dev/null
+            echo "✅ Created $(basename "$artifact").sbom.sigstore.json"
             ((SIGNED_COUNT++)) || true
           done
 
           echo "Generated SBOM bundles: ${SIGNED_COUNT}"
-          ls "${CALLER_DIST}"/*.sbom.sigstore.json 2>/dev/null || echo "ℹ️ No SBOM bundles generated (GoReleaser may not have generated SBOMs)"
+          if [ "$SIGNED_COUNT" -eq 0 ]; then
+            echo "::error::No Windows SBOM bundles were generated - this indicates a build problem"
+            exit 1
+          fi
+          ls "${CALLER_DIST}"/*.sbom.sigstore.json
 
       - name: Configure AWS credentials via OIDC
         uses: aws-actions/configure-aws-credentials@v5
diff --git a/scripts/validate-release-artifacts.sh b/scripts/validate-release-artifacts.sh
index 76e8404..4e9e701 100755
--- a/scripts/validate-release-artifacts.sh
+++ b/scripts/validate-release-artifacts.sh
@@ -123,53 +123,45 @@ for platform in $(echo "$MANIFEST" | jq -r '.assets | keys[]'); do
     continue
   fi
   
-  # Check binary signature (.sig + .cert files) - skip for MSI (derived artifact)
-  if [[ "$platform" == *-msi ]]; then
-    info "Skipping .sig/.cert check for $platform (derived artifact)"
-  else
-    SIG_FILE="${HREF}.sig"
-    CERT_FILE="${HREF}.cert"
-    if curl -sfL "$SIG_FILE" -o "$TEMP_DIR/${FILENAME}.sig" 2>/dev/null && \
-       curl -sfL "$CERT_FILE" -o "$TEMP_DIR/${FILENAME}.cert" 2>/dev/null; then
-      if cosign verify-blob \
-        --signature "$TEMP_DIR/${FILENAME}.sig" \
-        --certificate "$TEMP_DIR/${FILENAME}.cert" \
-        --certificate-oidc-issuer "$CERT_OIDC_ISSUER" \
-        --certificate-identity-regexp "$CERT_IDENTITY_REGEXP" \
-        "$TEMP_DIR/$FILENAME" > /dev/null 2>&1; then
-        pass "Binary signature verified: $platform"
-      else
-        fail "Binary signature verification failed: $platform"
-      fi
+  # Check binary signature (.sig + .cert files)
+  SIG_FILE="${HREF}.sig"
+  CERT_FILE="${HREF}.cert"
+  if curl -sfL "$SIG_FILE" -o "$TEMP_DIR/${FILENAME}.sig" 2>/dev/null && \
+     curl -sfL "$CERT_FILE" -o "$TEMP_DIR/${FILENAME}.cert" 2>/dev/null; then
+    if cosign verify-blob \
+      --signature "$TEMP_DIR/${FILENAME}.sig" \
+      --certificate "$TEMP_DIR/${FILENAME}.cert" \
+      --certificate-oidc-issuer "$CERT_OIDC_ISSUER" \
+      --certificate-identity-regexp "$CERT_IDENTITY_REGEXP" \
+      "$TEMP_DIR/$FILENAME" > /dev/null 2>&1; then
+      pass "Binary signature verified: $platform"
     else
-      fail "Binary signature files missing: $platform (.sig or .cert)"
+      fail "Binary signature verification failed: $platform"
     fi
+  else
+    fail "Binary signature files missing: $platform (.sig or .cert)"
   fi
 
-  # Check provenance attestation (skip for MSI - it's derived from the same binary as the zip)
-  if [[ "$platform" == *-msi ]]; then
-    info "Skipping provenance check for $platform (derived from zip)"
+  # Check provenance attestation
+  PROV_BUNDLE="${HREF}.provenance.sigstore.json"
+  if ! curl -sfL "$PROV_BUNDLE" -o "$TEMP_DIR/${FILENAME}.provenance.sigstore.json" 2>/dev/null; then
+    fail "Provenance bundle missing: $PROV_BUNDLE"
   else
-    PROV_BUNDLE="${HREF}.provenance.sigstore.json"
-    if ! curl -sfL "$PROV_BUNDLE" -o "$TEMP_DIR/${FILENAME}.provenance.sigstore.json" 2>/dev/null; then
-      fail "Provenance bundle missing: $PROV_BUNDLE"
+    # Verify provenance
+    if cosign verify-blob-attestation \
+      --bundle "$TEMP_DIR/${FILENAME}.provenance.sigstore.json" \
+      --type https://slsa.dev/provenance/v1 \
+      --certificate-oidc-issuer "$CERT_OIDC_ISSUER" \
+      --certificate-identity-regexp "$CERT_IDENTITY_REGEXP" \
+      "$TEMP_DIR/$FILENAME" > /dev/null 2>&1; then
+      pass "Provenance verified: $platform"
     else
-      # Verify provenance
-      if cosign verify-blob-attestation \
-        --bundle "$TEMP_DIR/${FILENAME}.provenance.sigstore.json" \
-        --type https://slsa.dev/provenance/v1 \
-        --certificate-oidc-issuer "$CERT_OIDC_ISSUER" \
-        --certificate-identity-regexp "$CERT_IDENTITY_REGEXP" \
-        "$TEMP_DIR/$FILENAME" > /dev/null 2>&1; then
-        pass "Provenance verified: $platform"
-      else
-        fail "Provenance verification failed: $platform"
-      fi
+      fail "Provenance verification failed: $platform"
     fi
   fi
 
-  # Check SBOM attestation (skip for checksums and MSI - only binary archives have SBOMs)
-  if [[ "$platform" == "checksums" || "$platform" == *-msi ]]; then
+  # Check SBOM attestation
+  if [[ "$platform" == "checksums" ]]; then
     info "Skipping SBOM check for $platform (not applicable)"
   else
     SBOM_BUNDLE="${HREF}.sbom.sigstore.json"