diff --git a/ods/ods-cli b/ods/ods-cli
index fc1b97d414..2da6f2eb5d 100755
--- a/ods/ods-cli
+++ b/ods/ods-cli
@@ -3800,7 +3800,9 @@ META
                 trap 'exit 143' TERM
                 # Finish privately before replacing an existing public file.
                 chmod 600 "$staged_archive" || exit 1
-                tar czf "$staged_archive" "$name" 2>/dev/null || exit 1
+                # COPYFILE_DISABLE stops macOS bsdtar adding AppleDouble `._*`
+                # members, which it hides from its own listing but importers see.
+                COPYFILE_DISABLE=1 tar czf "$staged_archive" "$name" 2>/dev/null || exit 1
                 [[ ! -d "$output" ]] || exit 1
                 mv -f -- "$staged_archive" "$output"
             ); then
@@ -3827,7 +3829,11 @@ META
 
             # Validate archive structure
             local archive_name
-            archive_name=$(tar tzf "$archive" 2>/dev/null | sed -n '1p' | cut -d/ -f1)
+            # Take the first real member, skipping AppleDouble `._*` entries: an
+            # archive exported from macOS before the guard above leads with
+            # `._<name>`, which GNU tar lists, and the preset name would otherwise
+            # resolve to `._<name>` and fail validation.
+            archive_name=$(tar tzf "$archive" 2>/dev/null | awk '!/(^|\/)\._/ { print; exit }' | cut -d/ -f1)
             [[ -z "$archive_name" ]] && error "Invalid archive structure"
 
             # Check if preset already exists
diff --git a/ods/scripts/ods-support-bundle.sh b/ods/scripts/ods-support-bundle.sh
index dcf36f82c6..7becd4fdaa 100755
--- a/ods/scripts/ods-support-bundle.sh
+++ b/ods/scripts/ods-support-bundle.sh
@@ -868,7 +868,12 @@ write_evidence
 write_manifest
 
 chmod -R go-rwx "$BUNDLE_DIR"
-(umask 077 && tar -czf "$ARCHIVE_PATH" -C "$OUTPUT_DIR" "$BUNDLE_NAME")
+# macOS `tar` (bsdtar) embeds AppleDouble `._*` metadata companions for files
+# that carry extended attributes. They unpack as real `._*` files wherever the
+# bundle is opened and break tooling that decodes bundle files as text.
+# COPYFILE_DISABLE tells bsdtar to omit them; GNU tar ignores it. Same guard as
+# the backup archive in ods-backup.sh.
+(umask 077 && COPYFILE_DISABLE=1 tar -czf "$ARCHIVE_PATH" -C "$OUTPUT_DIR" "$BUNDLE_NAME")
 
 if [[ "$JSON_OUTPUT" == "true" ]]; then
     write_summary_json
diff --git a/ods/tests/ci-suite.txt b/ods/tests/ci-suite.txt
index c315a28274..08290ddcf1 100644
--- a/ods/tests/ci-suite.txt
+++ b/ods/tests/ci-suite.txt
@@ -184,6 +184,7 @@ tests/test-preset-compatibility.sh
 tests/test-preset-diff.sh
 tests/test-preset-import-export.sh
 tests/test-preset-import-transaction.sh
+tests/test-preset-macos-appledouble.sh
 tests/test-preview-inspection.mjs
 tests/test-resolve-compose-nondict-service.sh
 tests/test-resolve-compose-symlinked-install.sh
diff --git a/ods/tests/test-preset-macos-appledouble.sh b/ods/tests/test-preset-macos-appledouble.sh
new file mode 100755
index 0000000000..67f6c9c84e
--- /dev/null
+++ b/ods/tests/test-preset-macos-appledouble.sh
@@ -0,0 +1,161 @@
+#!/usr/bin/env bash
+# Presets exported on macOS must import on every platform.
+#
+# macOS `tar` (bsdtar) writes AppleDouble `._*` metadata companions for files
+# carrying extended attributes, and puts `._<name>` ahead of `<name>/`. bsdtar
+# hides those members from its own `tar tzf` listing, so the exporting machine
+# sees a clean archive, but GNU tar lists them. `preset import` took the first
+# listed member as the preset name, so on Linux the name resolved to
+# `._<name>`, validation could not find `<name>/meta.txt`, and the import died
+# with "Invalid preset: missing meta.txt" while leaving the real preset
+# directory extracted on disk.
+#
+# Export now sets COPYFILE_DISABLE so new archives carry no such members, and
+# import skips them so archives already in circulation still work.
+#
+# Runs the real CLI against a throwaway install. No Docker is needed.
+set -euo pipefail
+
+ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+ODS_CLI="$ROOT_DIR/ods-cli"
+
+PASS=0
+FAIL=0
+pass() { PASS=$((PASS + 1)); printf '[PASS] %s\n' "$1"; }
+fail() { FAIL=$((FAIL + 1)); printf '[FAIL] %s\n' "$1" >&2; }
+
+TMP_DIR="$(mktemp -d)"
+trap 'rm -rf "$TMP_DIR"' EXIT
+
+# make_install <dir>: the minimal install the CLI accepts (check_install + sr_load)
+make_install() {
+    local dir="$1"
+    mkdir -p "$dir/lib" "$dir/extensions/services"
+    cp "$ODS_CLI" "$dir/ods-cli"
+    cp "$ROOT_DIR"/lib/*.sh "$dir/lib/"
+    : > "$dir/docker-compose.base.yml"
+}
+
+run_cli() {  # run_cli <install> <args...>
+    local install="$1"
+    shift
+    ODS_HOME="$install" bash "$install/ods-cli" "$@"
+}
+
+# ── Source contract: export must disable AppleDouble metadata ────────────────
+# Has teeth on every platform, including Linux CI where bsdtar's `._*` behavior
+# cannot be reproduced: a future edit that drops the guard fails here.
+if grep -Eq 'COPYFILE_DISABLE=[^ ]* +tar +czf' "$ODS_CLI"; then
+    pass "preset export guards the tar invocation with COPYFILE_DISABLE"
+else
+    fail "preset export must run 'tar czf' under COPYFILE_DISABLE to omit AppleDouble metadata"
+fi
+
+# ── Behavioral: an archive that already carries `._*` members must import ────
+# The archive is synthesized rather than produced by bsdtar, so it is identical
+# on every platform. The teeth are on Linux, which is where the bug bites and
+# where CI runs: GNU tar lists the `._<name>` member, so before the fix the
+# name resolved to `._shared-setup` and this import failed. macOS bsdtar hides
+# the member from its own listing, so there the check is a sanity check.
+make_appledouble_archive() {  # make_appledouble_archive <path> <preset_name>
+    python3 - "$1" "$2" <<'PY'
+import io, sys, tarfile
+
+archive, name = sys.argv[1], sys.argv[2]
+
+def add(tar, path, payload):
+    data = payload.encode()
+    info = tarfile.TarInfo(path)
+    info.size = len(data)
+    tar.addfile(info, io.BytesIO(data))
+
+with tarfile.open(archive, "w:gz") as tar:
+    # bsdtar emits the AppleDouble companion immediately before what it
+    # describes, so the top-level `._<name>` lands first — exactly where the
+    # CLI looked for the preset name. Only that member is modelled: the
+    # per-file companions play no part in resolving the name, and bsdtar
+    # would try to apply a synthetic one as real metadata on macOS.
+    add(tar, "._%s" % name, "Mac OS X AppleDouble payload")
+    directory = tarfile.TarInfo("%s/" % name)
+    directory.type = tarfile.DIRTYPE
+    directory.mode = 0o755
+    tar.addfile(directory)
+    add(tar, "%s/meta.txt" % name, "name=%s\n" % name)
+    add(tar, "%s/extensions.list" % name, "dashboard\n")
+PY
+}
+
+TARGET="$TMP_DIR/target"
+make_install "$TARGET"
+ARCHIVE="$TMP_DIR/shared-setup.tar.gz"
+make_appledouble_archive "$ARCHIVE" "shared-setup"
+
+if run_cli "$TARGET" preset import "$ARCHIVE" > "$TMP_DIR/import.out" 2>&1; then
+    if [[ -f "$TARGET/presets/shared-setup/meta.txt" ]]; then
+        pass "a macOS archive carrying AppleDouble members imports as 'shared-setup'"
+    else
+        fail "import reported success but presets/shared-setup/meta.txt is missing"
+    fi
+else
+    sed 's/^/    /' "$TMP_DIR/import.out"
+    fail "importing an archive with AppleDouble members failed"
+fi
+
+# The AppleDouble entry must never be mistaken for the preset itself.
+if [[ -d "$TARGET/presets/._shared-setup" ]]; then
+    fail "import created a preset directory from the AppleDouble member"
+else
+    pass "no preset directory is created from the AppleDouble member"
+fi
+
+# ── Regression guard: a clean archive still imports unchanged ────────────────
+CLEAN_SRC="$TMP_DIR/clean"
+mkdir -p "$CLEAN_SRC/plain-setup"
+printf 'name=plain-setup\n' > "$CLEAN_SRC/plain-setup/meta.txt"
+printf 'dashboard\n' > "$CLEAN_SRC/plain-setup/extensions.list"
+CLEAN_ARCHIVE="$TMP_DIR/plain-setup.tar.gz"
+COPYFILE_DISABLE=1 tar czf "$CLEAN_ARCHIVE" -C "$CLEAN_SRC" plain-setup
+
+if run_cli "$TARGET" preset import "$CLEAN_ARCHIVE" > "$TMP_DIR/clean.out" 2>&1 \
+    && [[ -f "$TARGET/presets/plain-setup/meta.txt" ]]; then
+    pass "an archive without AppleDouble members imports unchanged"
+else
+    sed 's/^/    /' "$TMP_DIR/clean.out"
+    fail "importing a clean archive regressed"
+fi
+
+# ── Round trip: export then import through the real CLI ──────────────────────
+SOURCE="$TMP_DIR/source"
+make_install "$SOURCE"
+(umask 077 && printf 'GPU_BACKEND=nvidia\n' > "$SOURCE/.env")
+run_cli "$SOURCE" preset save round-trip > "$TMP_DIR/save.out" 2>&1 \
+    || { sed 's/^/    /' "$TMP_DIR/save.out"; fail "preset save failed"; }
+
+ROUND_TRIP="$TMP_DIR/round-trip.tar.gz"
+if run_cli "$SOURCE" preset export round-trip "$ROUND_TRIP" > "$TMP_DIR/export.out" 2>&1; then
+    stray="$(python3 -c '
+import sys, tarfile
+names = tarfile.open(sys.argv[1]).getnames()
+print("\n".join(n for n in names if n.split("/")[-1].startswith("._")))
+' "$ROUND_TRIP")"
+    if [[ -n "$stray" ]]; then
+        echo "$stray" | sed 's/^/    stray member: /'
+        fail "exported archive contains AppleDouble members"
+    else
+        pass "exported archive carries no AppleDouble members"
+    fi
+
+    if run_cli "$TARGET" preset import "$ROUND_TRIP" > "$TMP_DIR/rt-import.out" 2>&1 \
+        && [[ -f "$TARGET/presets/round-trip/meta.txt" ]]; then
+        pass "exported preset imports on a second install"
+    else
+        sed 's/^/    /' "$TMP_DIR/rt-import.out"
+        fail "exported preset did not import"
+    fi
+else
+    sed 's/^/    /' "$TMP_DIR/export.out"
+    fail "preset export failed"
+fi
+
+printf '\n%d passed, %d failed\n' "$PASS" "$FAIL"
+[[ "$FAIL" -eq 0 ]]
diff --git a/ods/tests/test-support-bundle.sh b/ods/tests/test-support-bundle.sh
index 5c55ae47d3..9878e19934 100755
--- a/ods/tests/test-support-bundle.sh
+++ b/ods/tests/test-support-bundle.sh
@@ -168,6 +168,24 @@ else
     fail "archive does not contain manifest/evidence.json"
 fi
 
+# macOS bsdtar embeds AppleDouble `._*` companions unless COPYFILE_DISABLE is
+# set; they unpack as binary junk files throughout the bundle. bsdtar hides
+# them from its own `tar -tzf` listing, so list the raw members with tarfile.
+if python3 -c 'import sys, tarfile; print("\n".join(tarfile.open(sys.argv[1]).getnames()))' "$ARCHIVE_PATH" \
+    | grep -qE '(^|/)\._'; then
+    fail "archive contains AppleDouble (._*) metadata members"
+else
+    pass "archive has no AppleDouble metadata members"
+fi
+
+# Deterministic on every platform, including Linux CI where bsdtar's AppleDouble
+# behaviour cannot be reproduced: a future edit dropping the guard fails here.
+if grep -Eq 'COPYFILE_DISABLE=[^ ]* +tar +-czf' "$SUPPORT_SCRIPT"; then
+    pass "archive tar runs under COPYFILE_DISABLE"
+else
+    fail "archive tar must run under COPYFILE_DISABLE to omit AppleDouble metadata"
+fi
+
 if [[ -f "$BUNDLE_DIR/config/env.redacted" ]] && grep -q "DASHBOARD_API_KEY=\\[REDACTED\\]" "$BUNDLE_DIR/config/env.redacted"; then
     pass ".env is included only as redacted env"
 else