diff --git a/CHANGELOG.md b/CHANGELOG.md
index d5ab9c8..d9b459a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,10 @@ Format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); version
   master.cf service. After mail.log moved to `/data/log`, `postfix check`
   fatally rejected the path (default prefixes are only `/var` and
   `/dev/stdout`) and often left stderr/mail.log empty.
+- e2e: read `/data/setup-token` via `docker compose exec` (file is `0600`
+  panel-owned; host `ReadFile` got permission denied on CI). Reclaim `/data`
+  ownership before TempDir/stage cleanup so panel/postfix UIDs do not fail
+  Go's `RemoveAll`.
 
 ## [1.0.0] - 2026-08-09
 
diff --git a/build/postfix-config.sh b/build/postfix-config.sh
index 6d8a7be..c0df341 100644
--- a/build/postfix-config.sh
+++ b/build/postfix-config.sh
@@ -245,7 +245,7 @@ EOF
 # Validate the generated configuration; fail loudly if postconf produced
 # anything Postfix rejects, before the wrapper tries to start it.
 # #region agent log
-pcstep "pre-check maillog=$(postconf -qh maillog_file 2>&1) prefixes=$(postconf -qh maillog_file_prefixes 2>&1) postlog=$(postconf -qM postlog/unix-dgram 2>&1)"
+pcstep "pre-check maillog=$(postconf -h maillog_file 2>&1) prefixes=$(postconf -h maillog_file_prefixes 2>&1) postlog=$(postconf -M postlog/unix-dgram 2>&1)"
 # #endregion
 pcstep "postfix check"
 set +e
@@ -260,8 +260,8 @@ if [ "$ec" -ne 0 ]; then
 	cat "$MAIL_LOG_PATH" 2>&1 >&2 || true
 	# #region agent log
 	echo "postfix-config: --- postconf dump (debug) ---" >&2
-	postconf -qh maillog_file maillog_file_prefixes 2>&1 >&2 || true
-	postconf -qM postlog/unix-dgram 2>&1 >&2 || true
+	postconf -h maillog_file maillog_file_prefixes 2>&1 >&2 || true
+	postconf -M postlog/unix-dgram 2>&1 >&2 || true
 	# #endregion
 	exit "$ec"
 fi
diff --git a/test/e2e/hostname_gate_test.go b/test/e2e/hostname_gate_test.go
index ca654b0..cdb3fea 100644
--- a/test/e2e/hostname_gate_test.go
+++ b/test/e2e/hostname_gate_test.go
@@ -88,7 +88,14 @@ func runEntrypointBackground(t *testing.T, hostnameEnv string) (output string, s
 	}
 	name := "selfpost-e2e-hostname-check"
 	_ = exec.Command("docker", "rm", "-f", name).Run()
-	defer exec.Command("docker", "rm", "-f", name).Run()
+	defer func() {
+		// Make bind-mounted /data deletable by Go's TempDir cleanup: the panel
+		// leaves setup-token/db/opendkim owned by container UIDs (CI failed the
+		// subtest on testing.go TempDir RemoveAll even when start succeeded).
+		_ = exec.Command("docker", "exec", name, "sh", "-c",
+			"chown -R root:root /data && chmod -R a+rwX /data").Run()
+		_ = exec.Command("docker", "rm", "-f", name).Run()
+	}()
 
 	// #region agent log
 	if fi, err := os.Stat(dataDir); err == nil {
diff --git a/test/e2e/main_test.go b/test/e2e/main_test.go
index bd845b7..4135598 100644
--- a/test/e2e/main_test.go
+++ b/test/e2e/main_test.go
@@ -54,6 +54,10 @@ func TestMain(m *testing.M) {
 			fmt.Fprintf(os.Stderr, "\n==== logs: %s ====\n%s\n", svc, s.logs(svc))
 		}
 	}
+	// Panel/postfix-owned files under the /data bind mount outlive the
+	// container; reclaim ownership while selfpost is still up so a later
+	// prepareStage RemoveAll (or a local re-run) is not stuck on EACCES.
+	s.reclaimData()
 	s.down()
 	os.Exit(code)
 }
@@ -107,7 +111,7 @@ func TestE2E(t *testing.T) {
 	})
 
 	run("setup_and_login", func(t *testing.T) {
-		token, err := readSetupToken(h.stageDir)
+		token, err := readSetupToken(h)
 		if err != nil {
 			t.Fatalf("read setup token: %v", err)
 		}
diff --git a/test/e2e/panel_client.go b/test/e2e/panel_client.go
index b65e70a..5fb6044 100644
--- a/test/e2e/panel_client.go
+++ b/test/e2e/panel_client.go
@@ -7,8 +7,6 @@ import (
 	"net/http"
 	"net/http/cookiejar"
 	"net/url"
-	"os"
-	"path/filepath"
 	"regexp"
 	"strings"
 	"time"
@@ -60,26 +58,38 @@ func waitForPanelReady() error {
 	})
 }
 
-// readSetupToken reads the one-time setup URL SelfPost wrote to /data (bind
-// mounted at stageDir/data/setup-token) and returns just the token.
-func readSetupToken(stageDir string) (string, error) {
-	var raw []byte
+// readSetupToken reads the one-time setup URL from /data/setup-token inside
+// the running selfpost container. The file is mode 0600 owned by the panel
+// UID (security.md / setup.go); on a typical CI bind mount that is not the
+// host runner's UID, so a host-side os.ReadFile returns permission denied
+// even though the panel already wrote the token (CI: setup_and_login).
+// Reading via compose exec matches docs/guide.md ("docker compose exec
+// selfpost cat /data/setup-token").
+func readSetupToken(s *stack) (string, error) {
+	var raw string
 	err := waitFor("setup-token to appear", 30*time.Second, 300*time.Millisecond, func() (bool, error) {
-		b, err := os.ReadFile(filepath.Join(stageDir, "data", "setup-token"))
+		out, err := s.execIn("selfpost", "cat", "/data/setup-token")
 		if err != nil {
 			return false, err
 		}
-		raw = b
-		return len(b) > 0, nil
+		raw = out
+		return strings.TrimSpace(out) != "", nil
 	})
 	if err != nil {
 		return "", err
 	}
-	u, err := url.Parse(strings.TrimSpace(string(raw)))
+	u, err := url.Parse(strings.TrimSpace(raw))
 	if err != nil {
 		return "", fmt.Errorf("parse setup token file: %w", err)
 	}
-	return strings.TrimPrefix(u.Path, "/setup/"), nil
+	token := strings.TrimPrefix(u.Path, "/setup/")
+	// #region agent log
+	agentDebugLog("H9", "panel_client.go:readSetupToken", "setup token via docker exec", map[string]any{
+		"tokenLen": len(token),
+		"rawLen":   len(strings.TrimSpace(raw)),
+	})
+	// #endregion
+	return token, nil
 }
 
 func (c *panelClient) postForm(path string, form url.Values) (*http.Response, string, error) {
diff --git a/test/e2e/stack.go b/test/e2e/stack.go
index f39bb06..879af14 100644
--- a/test/e2e/stack.go
+++ b/test/e2e/stack.go
@@ -106,6 +106,14 @@ func (s *stack) down() {
 	_, _ = s.compose("down", "-v", "--remove-orphans")
 }
 
+// reclaimData chowns/chmods the /data bind mount from inside the still-running
+// selfpost container so the host test user can delete it afterwards. Files
+// written as panel/postfix (setup-token 0600, opendkim tree, sqlite) otherwise
+// leave EACCES on TempDir/stage cleanup (CI hostname-gate + prepareStage).
+func (s *stack) reclaimData() {
+	_, _ = s.execIn("selfpost", "sh", "-c", "chown -R root:root /data && chmod -R a+rwX /data")
+}
+
 // logs returns a service's combined stdout/stderr, for failure diagnostics.
 func (s *stack) logs(service string) string {
 	out, _ := s.compose("logs", "--no-color", service)
diff --git a/test/e2e/stage.go b/test/e2e/stage.go
index c036a75..3f51391 100644
--- a/test/e2e/stage.go
+++ b/test/e2e/stage.go
@@ -9,6 +9,7 @@ import (
 	"fmt"
 	"math/big"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"time"
 )
@@ -23,7 +24,7 @@ const selfpostHostname = "mail.e2e.test"
 // CoreDNS is authoritative for, and the sink-MX's dump directory. Called once
 // per run before `docker compose up`, so every run starts from a clean slate.
 func prepareStage(s *stack) error {
-	if err := os.RemoveAll(s.stageDir); err != nil {
+	if err := removeAllBestEffort(s.stageDir); err != nil {
 		return fmt.Errorf("clean stage dir: %w", err)
 	}
 	dirs := []string{"data", "certs", "dns-stage", "mail-stage"}
@@ -48,6 +49,17 @@ func prepareStage(s *stack) error {
 	return writeZone(s.stageDir, nil)
 }
 
+// removeAllBestEffort deletes path; if a previous run left container-UID files
+// on the bind mount, a root alpine one-shot removes them first.
+func removeAllBestEffort(path string) error {
+	if err := os.RemoveAll(path); err == nil {
+		return nil
+	}
+	_ = exec.Command("docker", "run", "--rm", "-v", path+":/wipe", "alpine:3.20",
+		"sh", "-c", "rm -rf /wipe/..?* /wipe/.[!.]* /wipe/*").Run()
+	return os.RemoveAll(path)
+}
+
 // writeSelfSignedCert generates a throwaway RSA key + self-signed certificate
 // for selfpostHostname, valid for a day — this stand never outlives that.
 // Postfix's smtpd_tls_security_level is "may" (opportunistic), not enforced,