diff --git a/install-server.sh b/install-server.sh
index 5d2eaf9..b504d1a 100755
--- a/install-server.sh
+++ b/install-server.sh
@@ -527,11 +527,11 @@ fi
 # no matter what grep says, so the check condemned a working binary.
 #
 # BOUNDED, because "does not run" and "does not finish" are different failures
-# and only one of them used to be handled. A bundle can block in dyld before
-# reaching main — Gatekeeper assessment on a bundle in /Applications does
-# exactly this (issue #25) — and an unbounded check then hangs the installer
-# forever with no output, no error, and no service. A verification step that
-# can wedge is worse than no verification step.
+# and only one of them used to be handled. A bundle carrying
+# com.apple.quarantine blocks in dyld before reaching main (issue #25), and an
+# unbounded check then hangs the installer forever with no output, no error,
+# and no service. A verification step that can wedge is worse than no
+# verification step.
 # run_bounded is defined above the source guard so the tests can reach it.
 
 # --help, NOT a bare invocation. `tacet` with no arguments now runs the agent
@@ -544,10 +544,31 @@ verify_rc=$?
 set -e
 
 if [[ "$verify_rc" -eq 124 ]]; then
+  # The headline goes through err(); the rest does not. err() prefixes every
+  # line with ERROR:, and fifteen of those is a wall nobody reads at the moment
+  # they are already stuck.
   err "installed ${APP_DST} but it did not finish starting within 20s."
-  err "The process blocks before reaching main — nothing it logs will say so."
-  err "A bundle in /Applications does this under Gatekeeper assessment (#25);"
-  err "installing to ~/Applications (no cask, no TACET_APP_DIR) is known-good."
+  cat >&2 <<EOF
+
+The process blocks before reaching main, so nothing it logs will say why.
+
+Almost always this is com.apple.quarantine on the bundle (issue #25). Nothing
+launches tacet through LaunchServices — launchd starts it and this script execs
+it — so the first-launch consent gate has nobody to answer it and the process
+waits forever. Notarization does not help; the gate is consent, not assessment.
+
+  xattr -p com.apple.quarantine ${APP_DST}
+
+Removing the attribute does NOT recover this path. The first blocked launch
+wedges the path itself, and neither deleting the xattr nor replacing the bundle
+clears it — only a path that has never wedged:
+
+  rm -rf ${APP_DST}
+  TACET_APP_DIR=~/Applications ./install-server.sh
+
+The Homebrew cask strips quarantine from 0.1.2 on, so a current
+'brew install --cask drycodeworks/tap/tacet' should not reach this message.
+EOF
   exit 1
 fi
 if [[ "$usage_out" != *"usage: tacet"* ]]; then
diff --git a/tests/test_install_server_args.py b/tests/test_install_server_args.py
index 7995c26..057072c 100644
--- a/tests/test_install_server_args.py
+++ b/tests/test_install_server_args.py
@@ -59,8 +59,8 @@ def test_the_usage_text_documents_the_env_overrides(self, tmp_path):
 class TestVerificationIsBounded:
     """The installed binary is executed to prove it works. That must not hang.
 
-    A bundle can block in dyld before reaching main — Gatekeeper assessment on
-    a bundle in /Applications does exactly that (#25). Unbounded, the installer
+    A bundle carrying com.apple.quarantine blocks in dyld before reaching main
+    (#25) — the consent gate has no UI to answer it. Unbounded, the installer
     waits forever: no output, no error, no service, nothing in any log.
     """
 
@@ -78,6 +78,21 @@ def test_a_timeout_is_reported_differently_from_a_broken_binary(self):
         code = SCRIPT.read_text()
         assert 'verify_rc" -eq 124' in code, "the timeout status must be handled"
 
+    def test_the_timeout_message_names_quarantine_and_the_real_recovery(self):
+        # This message is read by someone already stuck, so being wrong here is
+        # expensive. It used to blame /Applications and call ~/Applications
+        # "known-good", which is backwards: a quarantined bundle hangs in
+        # ~/Applications too, and an unquarantined one runs fine in
+        # /Applications. The variable is the xattr, not the directory.
+        code = SCRIPT.read_text()
+        timeout_branch = code[code.index('verify_rc" -eq 124'):code.index("Shared secret")]
+        assert "com.apple.quarantine" in timeout_branch, \
+            "the message must name the actual cause"
+        assert "TACET_APP_DIR" in timeout_branch, \
+            "the message must give a recovery that works"
+        assert "known-good" not in timeout_branch, \
+            "the disproved /Applications-vs-~/Applications advice is back"
+
     def test_the_fallback_exists_because_macos_ships_no_timeout(self):
         # A stock macOS has neither timeout(1) nor gtimeout. Relying on
         # coreutils would leave the check silently unbounded on exactly the